Laboratory for Topological Quantum Matter & Advanced Spectroscopy

Novel Quantum Matter & Quantum Many-Body Physics

Hasan Lab research is focused on exploring novel physics of quantum-many-body emergence, correlated electron motion, Bose-Einstein condensates, quantum coherence, and topological (weakly or strongly interacting, quantum entangled, topology and entanglement) emergence by combining novel spectroscopy, microscopy and transport methods. Deeper understanding and systematic control of quantum phenomena not only advance our knowledge of the laws of nature but also lay the foundation for future technologies. 

We develop tools capable of providing deep insights into the correlated motion of electrons in strongly correlated quantum systems and topological materials featuring emergent phenomena.  We also develop tools and methods to understand, theoretically predict and control emergent phenomena in materials.

We use advanced Spectroscopy, Transport; Microscopy (STM/STS) and other methods in our research to probe quantum degrees of freedom.  

Theoretical Prediction and experimental discovery of novel topological materials and exotic quantum phenomena:

PRIMARY FOCUS: 

On the experimental side, the Hasan lab focused on establishing direct experimental visualization of topological invariants via bulk-boundary contrast measurements, transforming topology from abstract mathematics into tangible physical reality of measurable materials in lab.

Research Description: https://www.amacad.org/person/m-zahid-hasan

News at Proc. National Academy of Sciences: https://www.pnas.org/doi/10.1073/pnas.1611504113

News at PHYSICS TODAY :

https://pubs.aip.org/physicstoday/article-abstract/62/4/12/391002/Exoti…

Novel and advanced state-of-the-art instrumentation (technique development) :

Princeton Lab: https://zahidhasangroup.scholar.princeton.edu/research-highlights

SLAC/Stanford :

https://www-ssrl.slac.stanford.edu/content/science/highlight/2020-02-29/discovery-topological-weyl-fermion-lines-and-drumhead-surface-states 

Princeton Physics: https://phy.princeton.edu/news

U.S. DOE : “New Phases of Quantum Matter”

https://www.energy.gov/science/articles/energy-secretary-brouillette-announces-2020-ernest-orlando-lawrence-award-winners

Bose-Einstein centenary lectures (100-year celebration of the birth of quantum physics) :

https://www.linkedin.com/feed/update/urn:li:activity:7276661044985380864/

SCIENTIFIC AMERICAN: “Topology Reshaping Physics”

https://www.scientificamerican.com/article/the-strange-topology-that-is-reshaping-physics/

Berkeley Lab (led by Princeton): https://newscenter.lbl.gov/2017/04/14/how-x-rays-pushed-topological-mat…

Lab History: Over the last two decades Hasan group has been active in generating novel ideas, methodologies and instrumentations to create next-generation advanced tools for quantum research and discovery

https://phy.princeton.edu/people/m-zahid-hasan

Hasan Princeton Lab Inventions, Breakthroughs & Patents ..

https://www.linkedin.com/in/mzahidhasan/details/projects/?profileUrn=urn%3Ali%3Afsd_profile%3AACoAAALEhvEBgM7947NrEynu1XFDkeRLUQ

Berkeley Lab (led by Princeton): https://newscenter.lbl.gov/2019/03/20/the-best-topological-conductor-ye…

Sir Nevill Mott (Nobel Laureate 1977) Lecture Series in Physics : https://www.lboro.ac.uk/departments/physics/events/sir-nevill-mott-lectures/

Inventions, Breakthroughs, Patents ..

https://www.linkedin.com/in/mzahidhasan/

 

“Topology as a fundamental principle (measurable bulk-boundary correspondence) behind the inner organization of quantum matter realized in bulk solids.” We have been developing methods and techniques to establish this 21st-century paradigm of physics in our Lab experimentally through a series of discoveries over the last two decades.

“Topological quantum matter is a new organizing principle for solids that has now been experimentally established across multiple distinct phases.”

 

New way of measuring topology: A Paradigm Shift:  “.. A paradigm shift in quantum materials research achieved through a new method to measure topological invariants precisely beyond old quantum Hall paradigm” (for details see, “Topological Invariants measured precisely and decisively without resorting to transport methods” RMP 82, 3045 (2010))
APS-Physics: "Topological Invariants via Spectroscopy (New Methods)" (https://absuploads.aps.org/presentation.cfm?pid=14503)

Topo Invariants precisely define a New Topo State of Matter which can be precisely measured via Spectroscopic measurements (no transport or quantum Hall transport is needed). This invited talk at APS-Physics elaborates this NEW method which enabled discovery of many NEW topological states of matter…

https://absuploads.aps.org/presentation.cfm?pid=14503

 

Topological Quantum Frontiers ...

Frontiers

New Phases of Matter required a new experimental method ..

Hasan team demonstrated methods to measure topological matter without measuring transport. Previous methods were based on Hall transport which is a century-old method of measuring topology. It is this new method of measuring topological invariant that led to a new experimental revolution in the field. … including many unpredicted and unexpected novel quantum phenomena not envisioned even in theory..

Experiment is the only means of knowledge at our disposal. Everything else is poetry, imagination” – Max Planck.

Quantum physics originated from ground-level experiments ..

Textbook inclusion

Textbook inclusion of Experimental Results from our Lab : A few of our results, including Topological Insulators and Weyl-Dirac Semimetals, are now included in many standard textbooks of condensed matter physics [see, for example, “Modern Condensed Matter Physics” by K. Yang and Steven Girvin (Yale University) ]

“Topological Invariants measured precisely and decisively without resorting to transport methods”

“.. A paradigm shift in quantum materials research achieved through a new method to measure topological invariants precisely beyond old quantum Hall paradigm” (for details see, “Topological Invariants measured precisely and decisively without resorting to transport methods” (RMP 82, 3045 (2010))

Topological Invariants measured via Spectroscopy ..

TIM

Textbook inclusion :

Textbook inclusion of Experimental Results from our Lab : A few of our results, including Topological Insulators and Weyl-Dirac Semimetals, are now included in many standard textbooks of condensed matter physics [see, for example, “Modern Condensed Matter Physics” by K. Yang and Steven Girvin (Yale University) ]

Our method of using advanced SPECTROSCOPIC techniques as novel methods to directly measure topological invariants in old and New Classes of quantum materials is now taught in text books world-wide.

New Methods ...

  • rt
  • TIM

Research at Hasan lab (Princeton University)

  • Laboratory for Topological Quantum Matter (2008-)

    DH
  • Laboratory for Topological Quantum Matter

    Laboratory for Topological Quantum Matter
  • Bose-Einstein centenary lectures on the birth of quantum physics

    t
  • Laboratory for Topological Quantum Matter

    suyang
  • Laboratory for Topological Quantum Matter

    p5
  • Laboratory for Topological Quantum Matter

    Group photo 1
  • Topological Quantum Matter

    t2

New Phases of Matter :

According to U.S. Department of Energy, these “experiments led to seminal discoveries of new phases of matter and new fermionic quasiparticles.” The research work on topological quantum matter “opened new areas in condensed matter physics and holds promise for future transformative applications in materials sciences” 

Source: https://www.energy.gov/science/articles/energy-secretary-brouillette-announces-2020-ernest-orlando-lawrence-award-winners

Non-QuantumHall-like Topological Matter

Hasan, M. Z., Xu, S.-Y. & Bian, G. 

Topological insulators, topological superconductors and Weyl fermion semimetals: discoveries, perspectives and outlooks. 

Phys. Scr. 2015, 014001 (2015).

“.. recent experimental discoveries of non-quantum-Hall-like topological insulators, topological superconductors, Weyl semimetals and other topological states of matter also signal a clear departure from the quantum-Hall-effect-like transport paradigm that has dominated the field since the 1980s. It is these new forms of matter that enabled realizations of topological-Dirac, Weyl cones, helical-Cooper-pairs, Fermi-arc-quasiparticles and other emergent phenomena in fine-tuned photoemission (ARPES) experiments since ARPES experiments directly allow the study of bulk-boundary (topological) correspondence. In this proceeding we provide a brief overview of the key experiments and discuss our perspectives regarding the new research frontiers enabled by these experiments. Taken collectively, we argue in favor of the emergence of 'topological-condensed-matter-physics' in laboratory experiments...” (Non-QuantumHall-like Topological Matter)

Quantum-Hall-like Topological Matter are described by Chern (or “fractional Chern numbers”) with or without magnetic fields.

Our primary focus is on new states of matter (Non-Quantum Hall-like topological matter).

A Paradigm Shift ...

For Topo Insulators, 𝜎𝑥𝑦 (Transport) = 0; all 4 “Topo Invariants” that define them must be measured via Spectroscopy probing Bulk-Boundary correspondence directly :

See, Review, Hasan-Kane RMP 82, 3045 (2010)

APS-Physics lecture: https://absuploads.aps.org/presentation.cfm?pid=14503

This (𝜎(Hall) = 0) leads to New Physics: Beyond all forms of quantum-Hall-like physics and their modern descendants

Quantum many-body physics at Hasan lab

Strongly correlated electron physics: 

Quantum many-body physics in doped Mott insulators, Charge-order and Superconductivity competition, Nematic order & fluctuations etc. 

Hasan et.al., Phys. Rev. Lett. 92, 246402 (2004); Phys. Rev. Lett. 96, 046407 (2006); Phys. Rev. Lett. 97, 186405 (2006); Phys. Rev. Lett. 96, 216405 (2006). Phys. Rev. Lett. 98, 117007 (2007) and Phys. Rev. Lett. 99, 167002 (2007). Phys. Rev. B 78, 184508 (2008); Phys. Rev. Lett. 103, 037002 (2009).  Nature’18, NaturePhys’19, PRL’19, PRL’20, NatureCom’20a, NatureCom’20b, NatureCom’20c, Nature’20, NatureMat’21, PRL’21, Science’19, Nature’19, Nature’22a, Nature’22b, PRL’22, NaturePhys’22, NatureCom’22, NatureCom’23a, NatureCom’23b, NaturePhys’23, NatureCom’24a, NatureCom’24b, NatureCom’24c, NatureMat’24, NaturePhysics'25

Lab history:

The terms "Topological Quantum Matter" & "Topological Dirac Insulator" were coined in 2007
https://phy.princeton.edu/people/m-zahid-hasan

Substantially responsible (90,000+ citations) for opening 5 major research fronts in modern condensed matter physics over last two decades:

  1. Topological Surface States and Topo Insulators: Discovery & Fundamental Properties

    Experiments started in 2004, completed in 2007, paper submitted in 2007 KITP proceeding: https://www.on.kitp.ucsb.edu/online/motterials07/hasan/ KITP’2007, Nature’08 (submitted in 2007), Nature’09a, Nature’09b, Science’09, NaturePhys’09, PRL’09, PRL’10, NatureMat’10, NaturePhys’11a, NaturePhysics’11b, NaturePhys’12, Science’13, NatureCom’13, NaturePhys’14a, NaturePhys’14b, NatureCom’14, PRL’15, ScienceAdv’17, NatureMat’22, NaturePhys 20, 1253 (2024). NaturePhys 20, 776 (2024), Nature 628, 527 (2024). 

    News on the discovery of topological surface states: https://newscenter.lbl.gov/2017/04/14/how-x-rays-pushed-topological-mat…

  2. Topological Magnets including Chern magnets: Discovery & Fundamental Properties

    Experiments started in 2008, completed in 2011, arXiv(2008), NatPhys’11, NaturePhys’12 (Chern gap in 2012), Nature’18, Science’19, Nature’20, PRL’21, Nature’22a, Nature’22b, NaturePhys’23, NatureCom’24  

    APS invited talk on the discovery : https://absuploads.aps.org/presentation.cfm?pid=14503

  3. Topological Weyl/Dirac semimetals: Discovery & Fundamental Properties

    Experiments started in 2011, completed in 2014. APS invited talk on the Discovery: https://absuploads.aps.org/presentation.cfm?pid=14503 Science’11, PRB’12, NatureCom’15 (submitted in 2014), Science’15a (submitted in 2014), Science’15b, NaturePhys’15, PRL’16, NatureCom’16a, NatureCom’16b, PRL’17a, PRL’17b, PRL’17c, NaturePhys’17, NatureCom’17, NatureMat’18, Science’19, Nature’18, Nature’19, PRl’20, NatureCom’20, PRL’23a, PRL’23b, NatureCom’23, NaturePhys’23, Nature’24   

  4. Topological Phase Transitions  

    Experiments started in 2009, completed in 2010, Science’11, PRL’12, NatureCom’12, NaturePhys’12, NatureCom’15, NaturePhys’15, Nature’18, Science’19, Nature’19, PRL’19  

    Topological Phase Transition & Texture Inversion: https://www.science.org/doi/10.1126/science.1201607#:~:text=In%20the%20….

  5. Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors: 

    Experiments started in 2017, completed in 2017, Nature’18, NaturePhys’19, PRL’19, PRL’20, NatureCom’20a, NatureCom’20b, NatureCom’20c, Nature’20, NatureMat’21, PRL’21, Science’19, Nature’19, Nature’22a, Nature’22b, PRL’22, NaturePhys’22, NatureCom’22, NatureCom’23a, NatureCom’23b, NaturePhys’23, NatureCom’24a, NatureCom’24b, NatureCom’24c, NatureMat’24

    Discovery of novel quantum phenomena in Topological kagome magnets and superconductors : https://www.nature.com/articles/s41586-022-05516-0

Key Inventions & patents related to the research fronts :

First example of Weyl semimetals and the methods for its discovery US Patent#10214797 “Method for production and identification of Weyl semimetal” (2016)

First example of room-temperature topological quantum edge state

Identification Procedure of Room-Temp. Quantum Spin Hall Topological Edge State

PATENT FILING Ref#:  24-4088-1 (2024)

Fabrication of Quantum Devices using intrinsic insulating topological materials

Quantum device using insulating topo. material” PATENT FILING Ref#: 24-4093-1 (2024)   

Research works have been featured in Physics Today, Physics World, Scientific American, Nature News, Science News, Discover magazine, New Scientist and similar media including Physics Today’s “Search & Discovery News” multiple times over the last two decades. According to U.S. Department of Energy, these “experiments led to seminal discoveries of new phases of matter and new fermionic quasiparticles.” The research work “opened new areas in condensed matter physics and holds promise for future transformative applications in materials sciences”  Source: https://www.energy.gov/science/articles/energy-secretary-brouillette-announces-2020-ernest-orlando-lawrence-award-winners

According to the American Academy, these  “results have extended our old textbook level understanding of quantum matter and are now being featured in many standard textbooks of condensed matter physics used in universities world-wide.”.

 

Strongly correlated electron physics: 

Quantum many-body physics in doped Mott insulators, Charge-order and Superconductivity competition, Nematic order & fluctuations etc. 

Hasan et.al., Phys. Rev. Lett. 92, 246402 (2004); Phys. Rev. Lett. 96, 046407 (2006); Phys. Rev. Lett. 97, 186405 (2006); Phys. Rev. Lett. 96, 216405 (2006). Phys. Rev. Lett. 98, 117007 (2007) and Phys. Rev. Lett. 99, 167002 (2007). Phys. Rev. B 78, 184508 (2008); Phys. Rev. Lett. 103, 037002 (2009).  Nature’18, NaturePhys’19, PRL’19, PRL’20, NatureCom’20a, NatureCom’20b, NatureCom’20c, Nature’20, NatureMat’21, PRL’21, Science’19, Nature’19, Nature’22a, Nature’22b, PRL’22, NaturePhys’22, NatureCom’22, NatureCom’23a, NatureCom’23b, NaturePhys’23, NatureCom’24a, NatureCom’24b, NatureCom’24c, NatureMat’24, NaturePhysics'25

Opening new vistas: .. field-creation..

impact

Weyl..

CN

New Methods ...

  • rt
  • TIM

Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors:

Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors: 

Experiments started in 2017, completed in 2017, Nature’18, NaturePhys’19, PRL’19, PRL’20, NatureCom’20a, NatureCom’20b, NatureCom’20c, Nature’20, NatureMat’21, PRL’21, Science’19, Nature’19, Nature’22a, Nature’22b, PRL’22, NaturePhys’22, NatureCom’22, NatureCom’23a, NatureCom’23b, NaturePhys’23, NatureCom’24a, NatureCom’24b, NatureCom’24c, NatureMat’24

Novel quantum phenomena in Topological kagome magnets and superconductors (Nature 2022) : 

https://www.nature.com/articles/s41586-022-05516-0

What is New?

What is New? Unlike string theory, topological physics in lower dimensional condensed matter systems is an experimental reality since the bulk-boundary correspondence can be probed experimentally in lower dimensions. Recent experimental discoveries of non-quantum-Hall-like topological insulators, topological superconductors, Weyl semimetals and other topological states of matter also signal a clear departure from the quantum-Hall-effect-like transport paradigm that has dominated the field since the 1980s. It is these new forms of matter that enabled realizations of topological-Dirac, Weyl cones, helical-Cooper-pairs, Fermi-arc-quasiparticles and other emergent phenomena in fine-tuned photoemission experiments since such experiments directly allow the study of band-inversion, spin-texture imaging, spin-momentum locking, bulk-boundary (topological) correspondence. Taken collectively, we argue in favor of the emergence of ‘topological-condensed-matter-physics’ in laboratory experiments for which a variety of theoretical concepts over the last 90 years (Dirac-Weyl topology, negative-Dirac-mass, Dirac-monopole-Berry charge, Aharonov-Bohm phase, C.Herring's exceptional points (modern Weyl node), Karplus-Luttinger theory (modern Berry curvature), 1979-SSH-chain, 1976-Jackiw-Rebbi and many foundational theories before and around 1970s – most topological theories are not new.. ) paved the way for modern experiments on Topological Materials ! Materials are not new either!

What is new? Advanced Spectroscopic experiments that enable precise determination of “Topological Invariants” (see, for a review, RMP 82, 3045 (2010)

https://www.amacad.org/person/m-zahid-hasan

Inventions, Breakthroughs & Patents :

#  Developed methods for determining Z2 topological invariants and Mirror Chern numbers from spin-ARPES experiments alone without referring to theory (Nature 2009, Science 2009, Science 2011). These detailed methods were used to demonstrate that the 3D Topological Insulators are a new and distinct state of matter, which cannot be reduced to multiple copies of IQH, and there is no spin Hall effect in 3D. The 3D state is thus an example of non-quantum-Hall-like topological matter and the first realization of topologically ordered bulk solid in nature (Physics World 2011, Physics Today 2010). 

 

#  Demonstrated that electrons on the surface of some spin-orbit materials form a topologically-ordered two dimensional gas with a non-trivial Berry's phase (arXiv:0812.2078 (2008), Nature 2009)

 

#  Developed methods for the demonstration of spin-momentum locking without utilizing any transport method (Nature 2009, Science 2009, Science 2011)

 

#  Developed methods for the determination of Chern invariant and Chern gap from spin-ARPES experiments  (Nature Physics 2012)

 

#  Developed methods and algorithms for the identification of chiral fermions (Weyl and other chiral fermions) from spectroscopic experiments without replying on band-structure measurements (Science 2015a, Nature Physics 2015, Science 2015b) 

 

#  Developed methods and algorithms for the identification of Fermi arc fermions "Criteria for Directly Detecting (Proving) Topological Fermi Arcs" (Phys. Rev. Lett. 116, 066802 (2016))

 

#  Demonstrated methods and algorithms for “Momentum-space imaging of Cooper pairing in a half-Dirac-gas Superconductor (based on a topological insulator)” (Nature Physics 10, 943 (2014))

 

#  Demonstrated Adiabatic continuation approach to theoretically predict topo. materials Working with Hsin Lin demonstrated that first-principles-based adiabatic continuation approach is a powerful and efficient tool for constructing topological phase diagrams and locating non-trivial topological insulator materials. Applied to real materials, results demonstrated the efficacy of adiabatic continuation for exploring topologically nontrivial alloying systems and for identifying new topological insulators even when the underlying lattice does not possess inversion symmetry, and the approaches based on parity analysis of Fu-Kane methods are not viable. (Nature Materials 9, 546 (2010); Phys. Rev. B 87, 121202(R) (2013).) 

 

#  Discovery (Theoretical Prediction & Experimental Demonstration) of Weyl semimetals -- Weyl fermion and topological Fermi arcs in spin-orbit materials (Science 349, 613 (2015); Science 347, 294 (2015). Nature Phys 11, 748 (2015))

 

#  Developed and demonstrated a novel artificial condensed matter lattice and a new platform for one-dim. topological phases (Science Advances 3, e1501692 (2017)) 

 

#  Demonstrated quantum transport in bulk insulating topological insulators and Quantum transport response of topological hinge modes in a topological insulator (Nature Physics 20, 776–782 (2024) and Nature Physics 10, 956-963 (2014))

 

#  First Observation of Chern gap in 2012 Hedgehog spin texture and Berry's phase tuning in a magnetic topological insulator (Nature Physics 8, 616 (2012))

 

#  First example of Weyl semimetals and the methods for its discovery US Patent#10214797 “Method for production and identification of Weyl semimetal” (2016)

 

#  Discovered and demonstrated Topological nodal-line (continuous Dirac/Weyl) semimetals (2015-2016) Led in the theoretical prediction and experimental discovery of topological nodal-line semimetals (Nature Commun (2016), arXiv 2015) and elucidated their nontrivial topological electronic structure including Dirac loop Fermi surfaces known as nodal rings (demonstrated in PbTaSe2 and TlTaSe2) (Nature Commun. 7:10556 (2016); Physical Review B (2016))  

 

#  Demonstrated Giant and anisotropic many-body spin–orbit tunability in a correlated topo. kagome magnet (NATURE 562, 91–95 (2018))

 

#  Demonstrated Quantum-limit Chern topological magnet (NATURE 583, 533 (2020))

 

#  Demonstrated Magnetic-field control of topological electronic response near room temperature in correlated Kagome magnets (Physical Review Letters 123, 196604 (2019)) 

 

#  Demonstrated Many-body Resonance in a Correlated Topological Kagome Antiferromagnet (Phys. Rev. Lett. 125, 046401 (2020))

 

#  Discovered and demonstrated Room-temperature quantum spin Hall edge state in a topological insulator (Nature Materials  21, 1111 (2022))

 

# First example of room-temperature topological quantum edge state

Identification Procedure of Room-Temp. Quantum Spin Hall Topological Edge State

PATENT FILING Ref#:  24-4088-1 (2024)

 

# Fabrication of Quantum Devices using Intrinsic Insulating Topological Materials

Quantum device using insulating topo. material” PATENT FILING Ref#: 24-4093-1 (2024)   

 

These research works have been featured in Physics Today, Physics World, Scientific American, Nature News, Science News, Discover magazine, New Scientist and similar media, including Physics Today’s “Search & Discovery News” multiple times over the last two decades.

Top-Ten Physics Discoveries of the last ten years by Nature Physics (2011)

Top-Ten Breakthrough of 2015 by Physics World

Several results included in modern textbooks of condensed matter physics (since 2018)

 

 

Unpredicted, unexpected results ..

pw

--

CN

Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors:

Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors: 

Experiments started in 2017, completed in 2017, Nature’18, NaturePhys’19, PRL’19, PRL’20, NatureCom’20a, NatureCom’20b, NatureCom’20c, Nature’20, NatureMat’21, PRL’21, Science’19, Nature’19, Nature’22a, Nature’22b, PRL’22, NaturePhys’22, NatureCom’22, NatureCom’23a, NatureCom’23b, NaturePhys’23, NatureCom’24a, NatureCom’24b, NatureCom’24c, NatureMat’24

Novel quantum phenomena in Topological kagome magnets and superconductors (Nature 2022) : 

https://www.nature.com/articles/s41586-022-05516-0

Discovery of 2D & 3D Topological Magnets :

Discovery of 2D & 3D Topological Magnets :

Theory and Experiments : “In this talk I present our* theoretical and experimental works on 2D and 3D topological magnets in novel Weyl and Dirac materials building up on earlier result but including recent results "A three-dimensional magnetic topological phase" Ilya Belopolski et.al., arXiv:1712.09992 (2017); "Topological quantum properties of chiral crystals" Guoqing Chang et.al., Nature Materials (2018); "Topological Hopf and Chain Link Semimetal States and Their Application to Co2MnGa" Physical Review Letters 119, 156401 (2017); "Magnetic Weyl fermion semimetals in the R-AlGe family of compounds" Physical Review B (2018) and Jiaxin Yin, Songtian Zhang et.al., "Giant and anisotropic many-body spin–orbit tunability in a strongly correlated kagome magnet" NATURE 562, 91–95 (2018). *Guoqing Chang, Bahadur Singh, Su-Yang Xu, Guang Bian, Shin-Ming Huang, Chuang-Han Hsu, Ilya Belopolski, Nasser Alidoust, Daniel S Sanchez, Hao Zheng, Hong Lu, Xiao Zhang, Yi Bian, Tay-Rong Chang, Horng-Tay Jeng, Arun Bansil, Han Hsu, Shuang Jia, Titus Neupert, Hsin Lin, Jia-Xin Yin, Songtian S. Zhang, Hang Li, Kun Jiang, Bingjing Zhang, Cheng Xiang, Hao Zheng, Tyler A. Cochran, Daniel Multer, Guang Bian, Kai Liu, Zhong-Yi Lu, Ziqiang Wang, Shuang Jia, Wenhong Wang, Biao Lian, Benjamin J. Wieder, Frank Schindler, Di Wu, Titus Neupert and Tay-Rong Chang” *DOE/BES (DE-FG-02-05ER46200) and GBMF4547 (EPIQS initiative)

https://absuploads.aps.org/presentation.cfm?pid=14503

Research Highlights

 

Discovery of Topological surface states

https://newscenter.lbl.gov/2017/04/14/how-x-rays-pushed-topological-matter-research-over-the-top/

https://absuploads.aps.org/presentation.cfm?pid=14503

PHYSICS TODAY: https://pubs.aip.org/physicstoday/article/62/4/12/391002/Exotic-spin-textures-show-up-in-diverse-materialsA?searchresult=1

 

Discovery of Topological magnets and topological chiral phenomena

https://arxiv.org/abs/1812.04466

https://absuploads.aps.org/presentation.cfm?pid=14503

 

Discovery of Topological Weyl phenomena

https://www.amacad.org/person/m-zahid-hasan

 

Discovery of novel quantum phenomena in Topological kagome magnets and superconductors 

https://research.princeton.edu/news/princeton-led-team-discovers-unexpe…

https://www.nature.com/articles/s41586-022-05516-0

 

Theoretical Prediction and experimental discovery of novel topological materials and quantum phenomena

https://www.amacad.org/person/m-zahid-hasan 

 

Strongly correlated electron physics: 

Quantum many-body physics in doped Mott insulators, Charge-order and Superconductivity competition, Nematic order & fluctuations etc. 

Hasan et.al., Phys. Rev. Lett. 92, 246402 (2004); Phys. Rev. Lett. 96, 046407 (2006); Phys. Rev. Lett. 97, 186405 (2006); Phys. Rev. Lett. 96, 216405 (2006). Phys. Rev. Lett. 98, 117007 (2007) and Phys. Rev. Lett. 99, 167002 (2007). Phys. Rev. B 78, 184508 (2008); Phys. Rev. Lett. 103, 037002 (2009).  Nature’18, NaturePhys’19, PRL’19, PRL’20, NatureCom’20a, NatureCom’20b, NatureCom’20c, Nature’20, NatureMat’21, PRL’21, Science’19, Nature’19, Nature’22a, Nature’22b, PRL’22, NaturePhys’22, NatureCom’22, NatureCom’23a, NatureCom’23b, NaturePhys’23, NatureCom’24a, NatureCom’24b, NatureCom’24c, NatureMat’24

Current Research :

Currently, we are exploring 2D and 3D quantum materials that feature a combination of strong correlation and topological phenomena.

This includes 2D materials that exhibit unconventional magnetism, topology, superconductivity and quantum Hall phenomena.

Topological superconductor platforms

Room Temperature topological materials

Artificial Condensed Matter Lattice, Artificial Topological Lattice

Topological kagome magnets and superconductors

Quantum spin-liquid candidates

Quantum Transport & Topology

 

Recent Invited Reviews:

  1. M. Z. Hasan et al., Discovery of Topological Magnets: New Developments."https://absuploads.aps.org/presentation.cfm?pid=14503(Link is external)
  2. M. Z. Hasan, S.-Y. Xu, I. Belopolski, S.-M. Huang, "Discovery of Weyl Fermion Semimetals and Topological Fermi Arc States" Ann. Rev. Cond. Mat. Phys. 8, 289-309 (2017).
  3. M. Z. Hasan et.al., "Weyl Semimetal Discovery Methods" United States Patent #10214797, 

    Nature Rev. Mater. 6, 784-803 (2021), Nature 612, 647-657 (2022).

  4. S. Jia, S. Xu, M. Z. Hasan, "Weyl Semimetals, Fermi Arcs and Chiral Quantum Anomalies

    Nature Mater. 15, 1140-1144 (2016), Science 349, 613-617 (2015).

  5. T. Neupert, M. Denner, J.-X. Yin, R. Thomale, M. Z. Hasan, "Kagome Lattice: Charge Order and Superconductivity in Kagome Materials

    Nature Physics 18, 137-143 (2022).

  6. J. Yin, B. Lian, M. Z. Hasan, "Topological Kagome Magnets & Superconductors

    Nature 612, 647-657 (2022).

Quantum Frontiers ...

Frontiers

What is New?

What is New? Unlike string theory, topological physics in lower dimensional condensed matter systems is an experimental reality since the bulk-boundary correspondence can be probed experimentally in lower dimensions. Recent experimental discoveries of non-quantum-Hall-like topological insulators, topological superconductors, Weyl semimetals and other topological states of matter also signal a clear departure from the quantum-Hall-effect-like transport paradigm that has dominated the field since the 1980s. It is these new forms of matter that enabled realizations of topological-Dirac, Weyl cones, helical-Cooper-pairs, Fermi-arc-quasiparticles and other emergent phenomena in fine-tuned photoemission experiments since such experiments directly allow the study of band-inversion, spin-texture imaging, spin-momentum locking, bulk-boundary (topological) correspondence. Taken collectively, we argue in favor of the emergence of ‘topological-condensed-matter-physics’ in laboratory experiments for which a variety of theoretical concepts over the last 90 years (Dirac-Weyl topology, negative-Dirac-mass, Dirac-monopole-Berry charge, Aharonov-Bohm phase, C.Herring's exceptional points (modern Weyl node), Karplus-Luttinger theory (modern Berry curvature), 1979-SSH-chain, 1976-Jackiw-Rebbi and many foundational theories before and around 1970s – most topological theories are not new.. ) paved the way for modern experiments on Topological Materials ! Materials are not new either!

What is new? Advanced Spectroscopic experiments that enable precise determination of “Topological Invariants” (see, for a review, RMP 82, 3045 (2010)

https://www.amacad.org/person/m-zahid-hasan

Recent Research & Publications

Topological Magnets & Superconductors

J. Yin, B. Lian, M. Z. Hasan, "Topological Kagome Magnets and Superconductors," 

Nature 612, 647-657 (2022).

Nature 602, 245-250 (2022).

Weyl & Chiral phenomena

S. Jia, S.-Y. Xu, and M. Z. Hasan, "Weyl Semimetals, Fermi Arcs and Chiral Anomalies,"

Nature Mater. 15, 1140–1144 (2016).

Nature Reviews Materials 6, 784–803 (2021)

Nature 604, 647-652 (2022).

 

Spin-ARPES & STM/STS Reviews

"Probing topological matter with scanning tunnelling microscopy (STM)," Nat. Rev. Phys. 3, 249-263 (2021).

"Topological Insulators, Topological Superconductors and Weyl Semimetals," Phys. Scr. T164, 014001 (2015).

Nature Reviews Physics 3, 249–263 (2021)

Charge-order & Superconductivity

T. Neupert, M. Denner, J. Yin, R. Thomale, M. Z. Hasan, "Charge-order and Superconductivity in Kagome Lattice Materials," Nature Phys. (2021).

K. Jiang et al., "Kagome Superconductors AV3Sb5," https://arxiv.org/abs/2109.10809

Nature Phys. 18, 137-143 (2022).

Chiral Crystals & Helicoidal physics

Chang et al., "Topological Quantum Properties of Chiral Crystals," 

Nature Mater. 17, 978-985 (2018).

"Discovery of Topological Chiral Crystals with Helicoid Arc Quantum States," https://arxiv.org/abs/1812.04466.

Nature 567, 500-505 (2019)

2D Materials & Quantum Devices

The magnetic genome of two-dimensional van der Waals materials ACS nano 16 (5), 6960-7079 (2022)

Tunable superconductivity coexisting with the anomalous Hall effect in 1T'-WS2; https://arxiv.org/abs/2501.05980

Transport response of topological hinge modes

Nature Physics 20, 776–782 (2024)

 

 

Novel Topological Matter

Belopolski et al., "Observation of a Linked Loop Quantum State in a Topological Magnet," 

Nature 604, 647-652 (2022).

Novel Topological Matter: Discovery of a hybrid topological quantum state 

Nature 628, 527 (2024)

Quantum Transport & Topology

Topological Quantum Transport : Transport response of topological hinge modes 

Nature Physics 20, 776–782 (2024)

Room T Topo Phenomena

Chang, Xu et al., "Room-temperature Magnetic Weyl Semimetal and Nodal Line Semimetal States in Co2TiX" https://arxiv.org/abs/1603.01255

Room-temperature quantum spin Hall edge state in a topological insulator 

Nature Materials  21, 1111–1115 (2022)

Ultrafast quantum phenomena

Unconventional photocurrent responses from chiral surface Fermi arcs 

Phys. Rev. Lett. 124, 166404 (2020) 

Photocurrent-driven transient symmetry breaking in the Weyl semimetal  

Nature Materials 21, 62–66 (2021).

M. Z. Hasan, In Proceedings Volume PC12419, SPIE; Ultrafast Phenomena and Nanophotonics XXVII (2023)

Fermi arc, correlations & Superconductivity

Coexistence of Bulk-Nodal and Surface-Nodeless Cooper Pairings in a Superconducting Topological Semimetal. 

Phys. Rev. Lett. 130, 046402 (2023). 

Phys. Rev. Lett. 130, 066402 (2023) 

Tunable topologically driven Fermi arc van Hove singularities. 

Nature Physics 19, 682 (2023). 

Quantum Phase Transitions

Unconventional Scaling of the Superfluid Density with the Critical Temperature in Transition Metal Dichalcogenides

Science Adv. 5, eaav8465 (2019)   

 Quantum Phase Transition of Correlated Iron-Based Superconductivity in LiFe1- xCoxAs

Phys. Rev. Lett. 123, 217004 (2019)                  

Artificial Condensed Matter Lattice

“A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases” 

Science Adv. 3 e1501692 (2017)
 

 

Nematic-Order & Quantum Control

Nematic-Order & Quantum Control: "Giant and anisotropic many-body spin–orbit tunability in a correlated kagome magnet," 

Nature 562, 91–95 (2018).

Nature 612, 647-657 (2022). (review)

Knotted Quantum Matter

Knotted Quantum Matter: Observation of a linked-loop quantum state in a topological magnet

Science 365, 1278-1281 (2019)

Nature 604, 647–652 (2022)

Bose-Einstein centenary lectures (2024)

What is NEW?

Unlike string theory, topological physics in lower dimensional condensed matter systems is an experimental reality since the bulk-boundary correspondence can be probed experimentally in lower dimensions. Recent experimental discoveries of non-quantum-Hall-like topological insulators, topological superconductors, Weyl semimetals and other topological states of matter also signal a clear departure from the quantum-Hall-effect-like transport paradigm that has dominated the field since the 1980s. It is these new forms of matter that enabled realizations of topological-Dirac, Weyl cones, helical-Cooper-pairs, Fermi-arc-quasiparticles and other emergent phenomena in fine-tuned photoemission experiments since such experiments directly allow the study of bulk-boundary (topological) correspondence. Taken collectively, we argue in favor of the emergence of ‘topological-condensed-matter-physics’ in laboratory experiments for which a variety of theoretical concepts over the last 90 years (Dirac-Weyl topology, negative-Dirac-mass, Dirac-monopole-Berry charge, Aharonov-Bohm phase, CHerring's exceptional points (modern Weyl node), Karplus-Luttinger theory (modern Berry curvature), SSH-chain, Jakiw-Rebbi and many foundational theories before 1970s – Topological theories are not new! ) paved the way for modern experiments on Topological Materials! (Materials are not new either)

What is new? Advanced Spectroscopic experiments that enable precise determination of “Topological Invariants” (see, for a review, RMP 82, 3045 (2010)

Discovery of 2D & 3D Topological Magnets :

Discovery of 2D & 3D Topological Magnets :

Theory and Experiments : “In this talk I present our* theoretical and experimental works on 2D and 3D topological magnets in novel Weyl and Dirac materials building up on earlier result but including recent results "A three-dimensional magnetic topological phase" Ilya Belopolski et.al., arXiv:1712.09992 (2017); "Topological quantum properties of chiral crystals" Guoqing Chang et.al., Nature Materials (2018); "Topological Hopf and Chain Link Semimetal States and Their Application to Co2MnGa" Physical Review Letters 119, 156401 (2017); "Magnetic Weyl fermion semimetals in the R-AlGe family of compounds" Physical Review B (2018) and Jiaxin Yin, Songtian Zhang et.al., "Giant and anisotropic many-body spin–orbit tunability in a strongly correlated kagome magnet" NATURE 562, 91–95 (2018). *Guoqing Chang, Bahadur Singh, Su-Yang Xu, Guang Bian, Shin-Ming Huang, Chuang-Han Hsu, Ilya Belopolski, Nasser Alidoust, Daniel S Sanchez, Hao Zheng, Hong Lu, Xiao Zhang, Yi Bian, Tay-Rong Chang, Horng-Tay Jeng, Arun Bansil, Han Hsu, Shuang Jia, Titus Neupert, Hsin Lin, Jia-Xin Yin, Songtian S. Zhang, Hang Li, Kun Jiang, Bingjing Zhang, Cheng Xiang, Hao Zheng, Tyler A. Cochran, Daniel Multer, Guang Bian, Kai Liu, Zhong-Yi Lu, Ziqiang Wang, Shuang Jia, Wenhong Wang, Biao Lian, Benjamin J. Wieder, Frank Schindler, Di Wu, Titus Neupert and Tay-Rong Chang” *DOE/BES (DE-FG-02-05ER46200) and GBMF4547 (EPIQS initiative)

https://absuploads.aps.org/presentation.cfm?pid=14503

Publications links

Topological Quantum Matter

 

 

Research Front-1

Topological Insulators: Discovery & Fundamental Properties

Experiments started in 2004, completed in 2007, paper submitted in 2007

https://newscenter.lbl.gov/2017/04/14/how-x-rays-pushed-topological-matter-research-over-the-top/(Link is external)

2007 KITP invited talk: https://www.on.kitp.ucsb.edu/online/motterials07/hasan/(Link is external)

A topological Dirac insulator in a quantum spin Hall phase. [submitted in 2007]

D. Hsieh, D. Qian, L. Wray, et al.; (PI: M. Z. Hasan) 

NATURE 452, 970 (2008). [submitted in 2007] 

Electrons on the surface of Bi2Se3 form a topologically-ordered two dimensional gas with a non-trivial Berry's phase (Discovery of topological-insulator class with a single Dirac cone in 2008)

Preprint at arXiv:0812.2078 (2008)

Observation of Unconventional Quantum Spin Textures in Topological Insulators. 

D. Hsieh, Y. Xia, L. Wray, et al.; (PI: M. Z. Hasan) 

SCIENCE 323, 5916 (2009). 

A tunable topological insulator in the spin helical Dirac transport regime. 

D. Hsieh, Y. Xia, D. Qian, et al.; (PI: M. Z. Hasan) 

NATURE 460, 1101 (2009). 

Observation of a large-gap topological-insulator class with a single Dirac cone on the surface

Y Xia, D Qian, D Hsieh, L Wray, A Pal, H Lin et., al. 

Nature Physics 5, 398-402 (2009)

Observation of Time-Reversal-Protected Single-Dirac-Cone Topological-Insulator States in Bi2X3 family 

D Hsieh, Y Xia, D Qian, L Wray et., al. 

Physical Review Letters 103, 146401 (2009)

Topological surface states protected from backscattering by chiral spin texture

P Roushan, J Seo, CV Parker, YS Hor, D Hsieh, D Qian et., al. 

NATURE 460, 1106-1109 (2009)

Half-Heusler ternary compounds as new multifunctional experimental platforms for topological quantum phenomena

H Lin, LA Wray, Y Xia, S Xu, S Jia, RJ Cava, A Bansil, MZ Hasan

Nature Materials 9, 546-549 (2010)

Single-Dirac-Cone Topological Surface States in the TlBiSe2 Class of Topological Semiconductors

H Lin, RS Markiewicz, LA Wray, L Fu, MZ Hasan, A Bansil

Physical Review Letters 105, 036404 (2010)

A topological insulator surface under strong Coulomb, magnetic and disorder perturbations

LA Wray, SY Xu, Y Xia, D Hsieh, AV Fedorov, YS Hor, RJ Cava, A Bansil, M. Z. Hasan

Nature Physics 7, 32-37 (2011)

Topological phase transition and texture inversion in a tunable topological insulator. 

S.-Y. Xu, Y. Xia, L.A. Wray, et al.; (PI: M. Z. Hasan) 

SCIENCE 332, 560 (2011). 

Hedgehog spin texture and Berry's phase tuning in a magnetic topological insulator. 

S.-Y. Xu, M. Neupane, C. Liu, et al.; (PI: M. Z. Hasan) 

Nature Physics 8, 616 (2012). 

“Momentum-space imaging of Cooper pairing in a half-Dirac-gas topological 

Superconductor (based on a topological insulator)” 

Su-Yang Xu, N. Alidoust, I. Belopolski et.al., (PI: M. Z. Hasan) 

Nature Physics 10, 943 (2014) 

Observation of topological surface state quantum Hall effect in an intrinsic three-dimensional topological insulator (quantum transport in bulk insulating topological insulators) 

Y Xu, I Miotkowski, C Liu, J Tian, H Nam, N Alidoust, J Hu, CK Shih, M. Z. Hasan, Y. Chen

Nature Physics 10, 956-963 (2014)

Room-temperature quantum spin Hall edge state in a higher-order topological insulator Bi4Br4 

Nana Shumiya, Md Shafayat Hossain, Jia-Xin Yin et.al., (PI: M. Z. Hasan) 

Nature Materials  21, 1111–1115 (2022)

A hybrid topological quantum state in an elemental solid

Md Shafayat Hossain, Frank Schindler et.al., (PI: M. Z. Hasan) 

NATURE 628, 527–533 (2024). 

Boundary modes of a charge density wave state in a topological material

Maksim Litskevich, Md Shafayat Hossain, S-B. Zhang, Zi-Jia Cheng et.al., (PI: M. Z. Hasan) 

Nature Physics 20, 1253–1261 (2024).

Quantum transport response of topological hinge modes in a topological insulator

Md Shafayat Hossain, Qi Zhang, Zhiwei Wang, (PI: M. Z. Hasan)  

Nature Physics 20, 776–782 (2024)

 

Research Front- 2

Topological Magnets: Discovery & Fundamental Properties

Experiments started in 2008, completed in 2008, paper submitted in 2008

Original preprint at arXiv:0812.2078(Link is external) (2008) (First Observation of Chern gap in 2012) 

APS invited talk on the Discovery: https://absuploads.aps.org/presentation.cfm?pid=14503(Link is external)

A topological insulator surface under strong Coulomb, magnetic and disorder perturbations

LA Wray, SY Xu, Y Xia, D Hsieh, AV Fedorov et.al., (PI: M. Z. Hasan)

Nature Physics 7, 32-37 (2011)

(First Observation of Chern gap in 2012) 

Hedgehog spin texture and Berry's phase tuning in a magnetic topological insulator. 

S.-Y. Xu, M. Neupane, C. Liu, et al.; (PI: M. Z. Hasan) 

Nature Physics 8, 616 (2012). 

Giant and anisotropic many-body spin–orbit tunability in a correlated topo. kagome magnet 

Jia-Xin Yin, Songtian S. Zhang, Hang Li et.al.; (PI: M. Z. Hasan) 

NATURE 562, 91–95 (2018). 

(Topological Magnetic Semimetals) Discovery of Weyl fermion lines and drumhead surface states in a room temp. topological magnet

Ilya Belopolski, K. Manna, Daniel Sanchez et.al., (PI: M. Z. Hasan) 

SCIENCE 365, 1278 (2019).

Topological Chiral Crystals with Helicoid Arc Quantum States 

Daniel Sanchez, Ilya Belopolski, Tyler Cochran et.al., (PI: M. Z. Hasan) 

NATURE 567, 500-504 (2019). 

Quantum-limit Chern topological magnet 

J-X. Yin, S.S. Zhang et.al., (PI: M. Z. Hasan) 

NATURE 583, 533–536 (2020). 

Rare Earth Engineering in RMn6Sn6 (R=Gd−Tm, Lu) Topological Kagome Magnets. 

Wenlong Ma, Xitong Xu, Jia-Xin Yin et.al., 

Phys. Rev. Lett. 126, 246602 (2021).

“Observation of a linked loop quantum state in a topological magnet” 

I. Belopolski, G. Chang, T. Cochran etal., (PI: M. Z. Hasan) 

NATURE 604, 647-652 (2022) 

A topological Hund nodal line antiferromagnet

Xian P. Yang, Yueh-Ting Yao, Pengyu Zheng et.al., (PI: M. Z. Hasan)

Nature Commun. 15, 7052 (2024)

 

Research Front- 3

Topological Weyl/Dirac semimetals: Discovery & Fundamental Properties

Experiments started in 2011, completed in 2014

APS invited talk on the Discovery: https://absuploads.aps.org/presentation.cfm?pid=14503(Link is external)

Topological phase transition and texture inversion (at 3D bulk Dirac point) in a tunable topological insulator. 

S.-Y. Xu, Y. Xia, L.A. Wray, et al.; (PI: M. Z. Hasan) 

SCIENCE 332, 560 (2011). 

Observation of Fermi Arc Surface States in a Topological Metal. 

S.-Y. Xu, C. Liu, S K. Kushwaha et.al., (PI: M. Z. Hasan) 

SCIENCE 347, 294 (2015). (paper submitted in 2014)

Discovery of a Weyl Fermion semimetal and topological Fermi arcs. 

S.-Y. Xu, I. Belopolski, N. Alidoust et.al., (PI: M. Z. Hasan) 

SCIENCE 349, 613 (2015). 

Discovery of topo. Weyl fermion lines and drumhead surface states in a room temp. magnet 

Ilya Belopolski, K. Manna, Daniel Sanchez et.al., (PI: M. Z. Hasan) 

SCIENCE 365, 1278 (2019).

Giant and anisotropic many-body spin–orbit tunability in a correlated kagome magnet 

Jia-Xin Yin, Songtian S. Zhang, Hang Li et.al.; (PI: M. Z. Hasan) 

NATURE 562, 91–95 (2018).

Topological Chiral Crystals with Helicoid Arc Quantum States (Topological Semimetals)

Daniel Sanchez, Ilya Belopolski, Tyler Cochran et.al., (PI: M. Z. Hasan) 

NATURE 567, 500-504 (2019).

Coexistence of Bulk-Nodal and Surface-Nodeless Cooper Pairings in a Superconducting Dirac Semimetal. 

Yang, X.P., Zhong, Y., Mardanya, S., Cochran, T.A., Chapai, R., Mine, A., Zhang, J., Sánchez-Barriga, J., Cheng, Z-J., Clark, O.J., Yin, J-X., Blawat, J., Cheng, G., Belopolski, I., Nagashima, T., Najafzadeh, S., Gao, S., Yao, N., Bansil, A., Jin, R., Chang, T-R., Shin, S., Okazaki, K. & Hasan, M.Z. 

Phys. Rev. Lett. 130, 046402 (2023).

Tunable topologically driven Fermi arc van Hove singularities. 

Sanchez, D.S., Cochran, T.A., Belopolski, I., Cheng, Z-J., Yang, X.P., Liu, Y., Hou, T., Xu, X., Manna, K., Shekhar, C., Yin, J-X., Borrmann, H., Chikina, A., Denlinger, J.D., Stro cov, V.N., Xie, W., Felser, C., Jia, S., Chang, G. & Hasan, M.Z. 

Nature Physics 19, 682 (2023).

Causal structure of interacting Weyl fermions in condensed matter systems. 

Chiu, W-C., Chang, G., Macam, G., Belopolski, I., Huang, S-M., Markiewicz, R., Yin, J-X., Cheng, Z-J., Lee, C-C., Chang, T-R., Chuang, F-C., Xu, S-Y., Lin, H., Hasan, M.Z.& Bansil, A. 

Nature Commun. 14, 2228 (2023).

Visualizing Higher-Fold Topology in Chiral Crystals. 

Cochran, T.A., Belopolski, I., Manna, et.al., (PI: M. Z. Hasan)

Phys. Rev. Lett. 130, 066402 (2023)

A hybrid topological quantum state in an elemental solid

Md Shafayat Hossain, Frank Schindler et.al., (PI: M. Z. Hasan) 

NATURE 628, 527–533 (2024).

 

Research Front-4

Topological Kagome Magnets & Superconductors

Opened several new unexpected research fronts in topological kagome research ..

Giant and anisotropic many-body spin–orbit tunability in a correlated kagome magnet 

Jia-Xin Yin, Songtian S. Zhang, Hang Li et.al.; (PI: M. Z. Hasan) 

NATURE 562, 91–95 (2018).

Quantum-limit Chern topological magnet (kagome magnet)

J-X. Yin, S.S. Zhang et.al., (PI: M. Z. Hasan) 

NATURE 583, 533–536 (2020). 

Unconventional chiral charge order in kagome superconductor KV3Sb5. 

Yu-Xiao Jiang, Jia-Xin Yin, M. Michael Denner, Nana Shumiya, Brenden R. Ortiz, Gang Xu, Zurab Guguchia, Junyi He, Md Shafayat Hossain, Xiaoxiong Liu, Jacob Ruff, Linus Kautzsch, Songtian S. Zhang, Guoqing Chang, Ilya Belopolski, Qi Zhang, Tyler A. Cochran, Daniel Multer, Maksim Litskevich, Zi-Jia Cheng, Xian P. Yang, Ziqiang Wang, Ronny Thomale, Titus Neupert, Stephen D. Wilson, M. Zahid Hasan. 

Nature Materials  20, 1353–1357 (2021).

Rare Earth Engineering in RMn6Sn6 (R=Gd−Tm, Lu) Topological Kagome Magnets. 

Wenlong Ma, Xitong Xu, Jia-Xin Yin et.al., 

Phys. Rev. Lett. 126, 246602 (2021).

Time-reversal symmetry-breaking charge order in a kagome superconductor

C. Mielke, D. Das, Jia-Xin Yin et.al.,  (Co-PI: M. Z. Hasan)

NATURE 602, 245 (2022) 

Topological Kagome Magnets and Superconductors

J. Yin, B. Lian, M. Z. Hasan 

NATURE 612, 647-657 (2022)

“Discovery of charge order and corresponding edge state in kagome magnet FeGe” 

Jia-Xin Yin, Yu-Xiao Jiang, Xiaokun Teng, Md. Shafayat Hossain et.al., (PI: M. Z. Hasan)

Phys. Rev. Lett. 129, 166401 (2022)

“Charge order and superconductivity in kagome materials” 

T. Neupert, M. Denner, J.-X. Yin, R. Thomale & M. Z. Hasan 

Nature Physics 18, 137 (2022)

Discovery of conjoined charge density waves in the kagome superconductor CsV3Sb5

H Li, G Fabbris, AH Said, JP Sun, YX Jiang, JX Yin, et.al.,

Nature Commun. 13, 6348 (2022)

Discovery of charge density wave in a correlated kagome lattice antiferromagnet 

X. Teng, L. Chen, F. Ye et.al., 

NATURE 609, 490-495 (2022)

Tunable unconventional kagome superconductivity in charge ordered RbV3Sb5 and KV3Sb5. 

Guguchia, Z., Mielke III, C., Das, D., Gupta, R., Yin, J-X., et.al., 

Nature Commun. 14, 153 (2023).

Hidden magnetism uncovered in charge ordered bilayer kagome material 

Z. Guguchia, D. J. Gawryluk, Soohyeon Shin, Z. Hao, et.al., 

Nature Commun. 14, 7796 (2023)

Tunable topologically driven Fermi arc van Hove singularities. 

Sanchez, D.S., Cochran, T.A., Belopolski, I., et.al., (PI: M. Z. Hasan)

Nature Physics 19, 682 (2023).

Visualizing Higher-Fold Topology in Chiral Crystals. 

Cochran, T.A., Belopolski, I., Manna, K., Yahyavi, M., Liu, Y., Sanchez, D.S., Yang, X.P., Multer, D., Yin, J-X., Borrmann, H., Chikina, A., Krieger, J.A., Sánchez-Barriga, J., Le Fèvre, P., Bertran, F., Strocov, V.N., Denlinger, J.D., Chang, T-R., Jia, S., Felser, C., Lin, H., Chang, G. & Hasan, M.Z. 

Phys. Rev. Lett. 130, 066402 (2023)

Tunable topologically driven Fermi arc van Hove singularities. 

Sanchez, D.S., Cochran, T.A., Belopolski, I., Cheng, Z-J., Yang, X.P., Liu, Y., Hou, T., Xu, X., Manna, K., Shekhar, C., Yin, J-X., Borrmann, H., Chikina, A., Denlinger, J.D., Stro cov, V.N., Xie, W., Felser, C., Jia, S., Chang, G. & Hasan, M.Z. 

Nature Physics 19, 682 (2023). 

Charge density wave in topological kagome metal ScV6Sn6

Yong Hu, Junzhang Ma, Yinxiang Li et.al., 

Nature Commun 15, 1658 (2024)

Depth-dependent study of time-reversal symmetry-breaking in the kagome superconductor AV3Sb5

J. N. Graham, C. Mielke III, D. Das et.al., 

Nature Commun 15, 8978 (2024). 

A topological Hund nodal line antiferromagnet

Xian P. Yang, Yueh-Ting Yao, Pengyu Zheng et.al., (PI: M. Z. Hasan)

Nature Commun. 15, 7052 (2024)

Van Hove annihilation and nematic instability on a kagome lattice

Yu-Xiao Jiang, Sen Shao, Wei Xia, M. Michael Denner et.al., (PI: M. Z. Hasan)

Nature Materials (2024). https://doi.org/10.1038/s41563-024-01914-z

Weyl ..

CN

Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors:

Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors: 

Experiments started in 2017, completed in 2017, Nature’18, NaturePhys’19, PRL’19, PRL’20, NatureCom’20a, NatureCom’20b, NatureCom’20c, Nature’20, NatureMat’21, PRL’21, Science’19, Nature’19, Nature’22a, Nature’22b, PRL’22, NaturePhys’22, NatureCom’22, NatureCom’23a, NatureCom’23b, NaturePhys’23, NatureCom’24a, NatureCom’24b, NatureCom’24c, NatureMat’24

Novel quantum phenomena in Topological kagome magnets and superconductors (Nature 2022) : 

https://www.nature.com/articles/s41586-022-05516-0

Topological Quantum Science & Engineering

Topological Quantum Science and Engineering: Hasan lab helped launch the field of Topological Insulators by directly detecting the novel surface states and thoroughly demonstrating their unusual topological properties using advanced spin-sensitive spectroscopic techniques (50,000+ citations). Subsequently, Hasan group has theoretically and experimentally discovered many novel classes of topological matter and topological phase transitions including Topological Magnets (via the demonstration of Chern gap in 2012) using novel instrumentations and innovative methods and introduced designed discovery methods. The field expanded to include topological semimetals, notably Weyl Semimetals, whose states mimic massless fermions considered in quantum field theory. In 2015 Hasan group observed the emergent Weyl fermions and novel topological Fermi arc surface states in several topological semimetals he and his team theoretically predicted in arsenide and other materials. His Weyl fermion work is based on his and his team's theoretical predictions in several spin-orbit materials. Subsequently, he has theoretically and experimentally discovered many novel classes of magnetic topological semimetals. He has also made groundbreaking contributions (theoretical and experimental) in the subfields of topological phase transitions, topological magnets in 2D and 3D, topological nodal-line and drumhead metals, topological magnetic semimetals, topological chiral crystals, topological Hopf link semimetals, topological superconductors, Helicoid-arc quantum states and Kagome magnets and materials, Chern magnets and charge-ordered Kagome superconductors enabled by innovative applications and development of experimental methods. He identified room temperature topological materials. A vast majority of his experimental discoveries are based on his and his team's theoretical predictions of topological materials. These materials are broadly important for future device applications with higher energy efficiency, as quantum information science platforms, and for exploring new emergent or many-body quantum physics. He has also contributed to the conceptual design and theoretical development of some of these topics and written several comprehensive review articles by invitation. The methodologies introduced by him to explore and discover topological materials and phenomena are being used by others world-wide to further advance the field and led to new discoveries. His experiments and methods have been seminal in giving rise to the field of "Topological Quantum Matter" with more than 100,000 citations (over 250 publications with h-factor 110+), which is now growing vigorously at the nexus of condensed matter physics, materials engineering, nano-science, device physics & quantum engineering, chemistry and relativistic quantum field theory as evidenced in all citation tracks. 

Recent Works :

Frontiers

Field creation ... (KITP lecture link)

t

Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors:

Unexpected and unpredicted novel (many-body, correlated) quantum phenomena in Topological Kagome Magnets & Superconductors: 

Experiments started in 2017, completed in 2017, Nature’18, NaturePhys’19, PRL’19, PRL’20, NatureCom’20a, NatureCom’20b, NatureCom’20c, Nature’20, NatureMat’21, PRL’21, Science’19, Nature’19, Nature’22a, Nature’22b, PRL’22, NaturePhys’22, NatureCom’22, NatureCom’23a, NatureCom’23b, NaturePhys’23, NatureCom’24a, NatureCom’24b, NatureCom’24c, NatureMat’24

Novel quantum phenomena in Topological kagome magnets and superconductors : https://www.nature.com/articles/s41586-022-05516-0

--

CN

New Methods ...

  • rt
  • TIM

What is New?

What is New? Unlike string theory, topological physics in lower dimensional condensed matter systems is an experimental reality since the bulk-boundary correspondence can be probed experimentally in lower dimensions. Recent experimental discoveries of non-quantum-Hall-like topological insulators, topological superconductors, Weyl semimetals and other topological states of matter also signal a clear departure from the quantum-Hall-effect-like transport paradigm that has dominated the field since the 1980s. It is these new forms of matter that enabled realizations of topological-Dirac, Weyl cones, helical-Cooper-pairs, Fermi-arc-quasiparticles and other emergent phenomena in fine-tuned photoemission experiments since such experiments directly allow the study of band-inversion, spin-texture imaging, spin-momentum locking, bulk-boundary (topological) correspondence. Taken collectively, we argue in favor of the emergence of ‘topological-condensed-matter-physics’ in laboratory experiments for which a variety of theoretical concepts over the last 90 years (Dirac-Weyl topology, negative-Dirac-mass, Dirac-monopole-Berry charge, Aharonov-Bohm phase, C.Herring's exceptional points (modern Weyl node), Karplus-Luttinger theory (modern Berry curvature), 1979-SSH-chain, 1976-Jackiw-Rebbi and many foundational theories before and around 1970s – most topological theories are not new.. ) paved the way for modern experiments on Topological Materials ! Materials are not new either!

What is new? Advanced Spectroscopic experiments that enable precise determination of “Topological Invariants” (see, for a review, RMP 82, 3045 (2010)

https://www.amacad.org/person/m-zahid-hasan