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"A speckle of dust"



Topological Surface States during 2005-2007 at Berkeley Lab
"Search and Discovery" news at Physics Today

Topological Surface States (3D-TI topology) reported in 2007 at Kavil-KITP proceeding


Physics Today (2020)

10+ group members at Hasan lab recognized for high-impact research:
Lab members including Alidoust, Belopolski, Bian, G.Chang, T.Chang, Hasan, Neupane, Qian, Sanchez, Zheng, Xu - all listed as
"Highly-Cited Researchers" (2019)
by the Institute for Scientific Information (Clarivate Analytics) based on Web of Science


Discovering a 2D Topological Insulator (1988-type) in a natural 2D quantum magnet


Discovery of Topological Magnets in 2D and 3D (Chern, Kagome and Weyl magnets)

Discovery of a quantum limit Chern magnet TbMn6Sn6 (NATURE 2020)

Theoretical discovery of Bi2Se3 class as Topo.Insulators (2008)
News at Nature Physics mentions our theoretical contribution in the discovery of Bi2Se3 as 3DTIs (2009)


New Topological Phases of Matter (2007--)
[[Topological phases of matter have been long known in 1D in 1970s (Jackiw-Rebbi model, SSH chain, Haldane chain etc.) and 2D in 1980s (quantum Hall-like 2D effects shown by first versions of 2D Topological Insulators, 1980),
Nature News on 2016 Physics


Recent (new) development (2007-) is the 3D topological insulators and related materials.
The term "topological insulator" was coined in 2007 to describe the 3D topological states (in contrast to various forms of 1D chains or the quantum Hall-like 2D effects exhibited by all types of 2D Topo. Insulators including Haldane model and Thouless-type (TKNN) models.]]

Nature News (Homepage, July 2017) : ..Topology Reshaping Physics

Topological Insulators in (2007)

"Search & Discovery" PHYSICS TODAY (2009)

KITP program on "Topological Insulators and Superconductors"

A vast majority of our experimental works are based on our own theoretical predictions of topological materials (link)

(NEWS) "By considering the topology of chiral crystals, a new type of massless fermion, connected with giant arc-like surface states, are predicted. Such Kramers–Weyl fermions should manifest themselves in a wide variety of chiral materials." News at Nature Materials 2018
"Topological Insulators" and "Weyl Semimetals" highlighted by NATURE's Insight on Quantum Materials
along with superconductivity and spin liquids.

Discovery (Theoretical and Experimental) of a large-gap topological-insulator class with a single Dirac cone on the surface
arXiv version
;
Y.Xia, D.Qian, L.A.Wray, D.Hsieh et al., [submitted 2008] Nature Physics 5, 398 (2009)
;


Theoretical discovery of Weyl semimetal class TaAs (PhysicsWorld 2015)

Discovery of topological Weyl fermion lines and drumhead surface states in a room temperature magnet ( Science 2019 )
is based on our theoretical prediction of Weyl loops and topological surface states in a room temperature magnet ( PRL 2017 )

Science Talk (Physics-Next, PRL/APS-Physics): ..Quantum Fields to Condensed Matter: New Topological Phases of Matter in Natural and Artificial Materials

PhysicsWorld (2016): APS March Meeting

American Physical Society (APS-Physics) Meeting : Weyl Topological Semimetals: Theory and Experiment

Weyl Semimetals, Fermi Arcs and Chiral Anomalies Nature Materials (2016)

"Discovery of New Topological Phases of Matter" (Lawrence Berkeley Lab, 2017)

Half-Heuslers as new multifunctional experimental platforms for topological quantum phenomena (2010)



 


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Topologically protected Single Dirac Cone (Spin-Textured)
Nature Physics N&V
 
 
DS


Moore Symposium Lecture (2014)
 
 
 

Research Highlights:


First five experimental papers on 3DTI (Topological Insulators)


KITP Talk Proc. (2007)

KITP Talk Proc. (2008) "The Hydrogen Atom of Topological Insulator"

"Search&Discovery" Physics Today

A topological Dirac insulator in a quantum spin Hall phase
Nature 452, 970 (2008)
;
D.Hsieh, D.Qian, Y.Xia et.al., [April, '08] Submitted.(2007)

Observation of Unconventional Quantum Spin Textures in Topological Insulators
Science 323, 919 (2009)
;
D.Hsieh, Y.Xia, L.A.Wray et al., [February, '09] Submitted.(2008)

Discovery (Theoretical and Experimental) of a large-gap topological-insulator class with a single Dirac cone on the surface
arXiv version (2008)
;
Y.Xia, D.Qian, L.A.Wray, D.Hsieh et al., [May '09] Submitted.(2008)
Nature Physics 5, 398 (2009);
Extended version at
A tunable topological insulator in the spin helical Dirac transport regime
Nature 460, 1101 (2009)
;
D.Hsieh, Y.Xia, D.Qian et.al., Submitted.(2009)

p-type Bi2Se3 for topological insulator and low-temperature thermoelectric applications.
Phys.Rev.B 79, 195208 (2009)
;
Y.Hor, A.Richardella, Y.Xia, D.Hsieh et.al., [May '09] Submitted.(2009)

Experimental Realization of a Three-Dimensional Topological Insulator Bi2Te3
Science 325,178 (2009)
;
Y.L.Chen, J.Analytis et al., [Stanford] [June '09] Submitted.(Mar. 2009)


 
  DS  
  DS  
  PhysicsWorld News: "Weyl fermions are spotted at long last"
Discovery of Weyl fermion named a 'breakthrough of the year' by Physics World
News at Lawrence Berkeley National Laboratory (LBNL), MIT physics news
Physics Highlights of the Year 2015 (Physics - American Physical Society)

 
 

First papers on Weyl fermion semimetals


A Weyl Fermion semimetal with surface Fermi arcs in the transition metal monopnictide TaAs class
Nature Commun. 6:7373 (2015)
;
S.-M. Huang, S.-Y. Xu, I. Belopolski et al., Submitted (Nov 2014).

Discovery of a Weyl Fermion semimetal and topological Fermi arcs
Science 349, 613 (2015)
;
S.-Y. Xu, I. Belopolski, N. Alidoust et.al., Submitted (Feb 2015).

Weyl Semimetal Phase in Noncentrosymmetric Transition-Metal Monophosphides
Phys. Rev. X 5, 011029 (2015)
;
H. Weng, C. Fang, Z. Fang et al., Submitted (Jan 2015).

Experimental Discovery of Weyl Semimetal TaAs
Phys. Rev. X 5, 031013 (2015)
;
B. Q. Lv, H. M. Weng, B. B. Fu et.al., Submitted (July 2015).


 
 

Weyl Fermion Semimetals


Topological electronic structure and Weyl semimetal in the TlBiSe2 class of semiconductors
B. Singh, A.h Sharma, H. Lin, M. Z. Hasan, R. Prasad, and A. Bansil
Physical Review B 86, 115208 (2012)


Weyl Fermion Semimetal and Fermi arcs: TaAs,TaP, NbAs, NbP, SrSi2

Theoretical Prediction: A Weyl Fermion semimetal with surface Fermi arcs in the transition metal monopnictide TaAs class
S.-M. Huang, S.-Y. Xu, I. Belopolski, C.-C. Lee, G. Chang, B. Wang, N. Alidoust, G. Bian, M. Neupane, C. Zhang, S. Jia, A. Bansil, H. Lin, M. Z. Hasan
Nature Commun. 6:7373 (2015) (submitted Nov. 2014)

Experimental Discovery:
Discovery of a Weyl Fermion semimetal and topological Fermi arcs
S.-Y. Xu, I. Belopolski, N. Alidoust, M. Neupane, G. Bian, C. Zhang, R. Sankar, G. Chang, Z. Yuan, C.-C. Lee, S.-M. Huang, H. Zheng, J. Ma, D. S. Sanchez, B. Wang, A. Bansil, F. Chou, P. P. Shibayev, H. Lin, S. Jia, and M. Z. Hasan
Science 349, 613 (2015)

Discovery of a Weyl Fermion state with Fermi arcs in niobium arsenide
S.-Y. Xu, N. Alidoust, I. Belopolski, Z. Yuan, G. Bian, T.-R. Chang, H. Zheng, V. Strocov, D. S. Sanchez, G. Chang, C. Zhang, D. Mou, Y. Wu, L. Huang, C.-C. Lee, S.-M. Huang, B. Wang, A. Bansil, H.-T. Jeng, T. Neupert, A. Kaminski, H. Lin, S. Jia, and M. Z. Hasan
Nature Physics 11, 748 (2015)

Experimental discovery of a topological Weyl semimetal state in TaP
S.-Y. Xu, I. Belopolski, D. S. Sanchez, C. Guo, G. Chang, C. Zhang, G. Bian, Z. Yuan, H. Lu, Yi. Feng, T.-R. Chang, P. P. Shibayev, M. L. Prokopovych, N. Alidoust, H. Zheng, C.-C. Lee, S.-M. Huang, R. Sankar, F. Chou, C.-H. Hsu, H.-T. Jeng, A, Bansil, T. Neupert, V. N. Strocov, H. Lin, S. Jia, M. Z. Hasan
Science Advances 10, 1501092 (2015)

Transport Experiments: Tantalum Monoarsenide: an Exotic Compensated Semimetal
C. Zhang, Z. Yuan, S.-Y. Xu, Z. Lin, B. Tong, M. Z. Hasan, J. Wang, C. Zhang, S. Jia
arXiv:1502.00251

Observation of the Adler-Bell-Jackiw chiral anomaly in a Weyl semimetal
C. Zhang, S.-Y. Xu, I. Belopolski, Z. Yuan, Z. Lin, B. Tong, N. Alidoust, C.-C. Lee, S.-M. Huang, H. Lin, M. Neupane, D. S. Sanchez, H. Zheng, G. Bian, J. Wang, C. Zhang, T. Neupert, M. Z. Hasan, S. Jia
To appear Nature Commun. (2016)

Observation of Fermi Arc Surface States in a Topological Metal

S.-Y. Xu, C. Liu, S. Kushwaha, R. Sankar, J. Krizan, I. Belopolski, M. Neupane, G. Bian, N. Alidoust, T.-R. Chang, H.-T. Jeng, C.-Y. Huang, W.-F. Tsai, H. Lin, P. P. Shibayev, F. Chou, R. J. Cava, and M. Zahid Hasan

Science 347, 294 (2015)

New type of Weyl semimetal with quadratic double Weyl fermions

S.-M. Huang, S.-Y. Xu, I. Belopolski, C.-C. Lee, G. Chang, B. Wang, N. Alidoust, M. Neupane, H. Zheng, D. Sanchez, A. Bansil, G. Bian, H. Lin, and M. Z. Hasan

PNAS 113, 1180 (2015)

Recent developments:

Unconventional transformation of spin Dirac phase across a topological quantum phase transition
S.-Y. Xu, M. Neupane, I. Belopolski et al.;
Nat. Commun. 6:6870 doi: 10.1038/ncomms7870 (2015).

Observation of non-Kondo-like electronic structure in YbB6
M. Neupane, S.-Y. Xu, N. Alidoust, G. Bian, D.-J. Kim, C. Liu, I. Belopolski, T.-R. Chang, H.-T. Jeng, T. Durakiewicz, H. Lin, A. Bansil, Z. Fisk, M. Z. Hasan;
Phy. Rev. Lett. 114, 016403 (2015)

Dirac mass generation from crystal symmetry breaking on the surfaces of topological crystalline insulators
I. Zeljkovic, Y. Okada, M. Serbyn, R. Sankar, D. Walkup, W. Zhou, J. Liu, G. Chang, Y. J. Wang, M. Z. Hasan, F. Chou, H. Lin, A. Bansil, L. Fu, V. Madhavan;
Nature Materials 14, 318 (2015)

Momentum space imaging of Cooper pairing in a half-Dirac-gas topological superconductor (a helical 2D topological superconductor)

S.-Y. Xu, N. Alidoust, I. Belopolski, A. Richardella, C. Liu, M. Neupane, G. Bian, S.-H. Huang, R. Sankar, C. Fang, B. Dellabetta, W. Dai, Qi Li, M. J. Gilbert, F. Chou, N. Samarth, M. Z. Hasan;

Nature Physics 10, 943 (2014)

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

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

Nature Physics 10, 956 (2014)

Mapping the unconventional orbital texture in topological crystalline insulators
I. Zeljkovic, Y. Okada, C.-Y. Huang, R. Sankar, D. Walkup, W. Zhou, M. Serbyn, F. Chou, W.-F. Tsai, H. Lin, A. Bansil, L. Fu, M. Z. Hasan, V. Madhavan;
Nature Physics 10, 572 (2014)

Controlling transport of topological and trivial surface states in a topological insulator
Y. Xu, I. Miotkowski , C. Liu, J.Tian, H. Nam, N. Alidoust , J. Hu , C-K. Shih , M. Z. Hasan, Y. Chen;
Nature Materials (submitted) (2014)

Observation of a topological 3D Dirac semimetal phase in Cd3As2

M. Neupane, S.-Y. Xu, R. Sankar, N. Alidoust, G. Bian, C. Liu, I. Belopolski, T.-R. Chang, H.-T. Jeng, H. Lin, A. Bansil, F. Chou, M. Z. Hasan 

Nature Commun. 5, 3786 (2014)

Observation of bulk 3D Dirac multiplet, topological semimetal phase and spin states in Na3Bi

S.-Y. Xu, R. Sankar, N. Alidoust, G. Bian, C. Liu, I. Belopolski, T.-R. Chang, H.-T. Jeng, H. Lin, A. Bansil, F. Chou, M. Z. Hasan 

Preprint (2013)

Tuning a Schottky barrier in a photoexcited topological insulator with transient Dirac cone electron-hole asymmetry (Time-resolved ARPES)

Y. M. Hajlaoui, E. Papalazarou, J. Mauchain, L. Perfetti, A. Taleb-Ibrahimi, F. Navarin, M. Monteverde, P. Auban-Senzier, C.R. Pasquier, N. Moisan, D. Boschetto, M. Neupane, M.Z. Hasan, T. Durakiewicz, Z. Jiang, Y. Xu, I. Miotkowski, Y.P. Chen, S. Jia, H.W. Ji, R.J. Cava, M. Marsi;

Nature Commun. 5, 3003 (2014)

Observation of Quantum-Tunneling Modulated Spin Texture in Ultrathin Topological Insulator Bi2Se3 Films

M. Neupane, A. Richardella, J. Sanchez-Barriga, S.-Y. Xu, N. Alidoust, I. Belopolski, C. Liu, G. Bian, D. Zhang, D. Marchenko, A. Varykhalov, O. Rader, M. Leandersson, T.n Balasubramanian, T.-R. Chang, H.-T. Jeng, S. Basak, H. Lin, A. Bansil, N. Samarth, M. Z. Hasan

Nature Commun. 5, 3841 (2014)

Observation of Dirac node formation and mass acquisition in a topological crystalline insulator

Y. Okada, M. Serbyn, H. Lin, D. Walkup, W. Zhou, C. Dhital, M. Neupane, Suyang Xu, Y. Wang, R. Sankar, F. Chou, A. Bansil, M. Z. Hasan, S. Wilson, L. Fu, V. Madhavan

Science 341, 1496 (2013)

Surface States in a Topological Kondo Insulator Candidate

M. Neupane, N. Alidoust, S.-Y. Xu, T. Kondo, D.-J. Kim, C. Liu, I. Belopolski, T.-R. Chang, H.-T. Jeng, T Durakiewicz, L. Balicas, H.. Lin, A. Bansil, S Shin, Z. Fisk, M. Z. Hasan

Nature Commun. 4, 2991 (2013)


Magnetic Topological Insulators: Hedgehog spin texture and Berry's phase tuning in a magnetic topological insulator

S.-Y. Xu, M. Neupane, C. Liu, D. Zhang, A. Richardella, L. A. Wray, N. Alidoust, M. Leandersson, T. Balasubramanian, J. Sanchez-Barriga, O. Rader, G. Landolt, B. Slomski, J.H. Dil, J. Osterwalder, T.-R. Chang, H.-T. Jeng, H. Lin, A. Bansil, N. Samarth, M. Z. Hasan

Nature Physics 8, 616 (2012)


Topological phase transition and texture inversion in a tunable topological insulator

S.-Y.Xu Y. Xia, L. A. Wray, S. Jia, F. Meier, J. H. Dil, J. Osterwalder, B. Slomski, A. Bansil, H. Lin, R. J. Cava, M. Z. Hasan

Science 332, 560 (2011)


Observation of topological order in a superconducting doped topological insulator

L. A. Wray, S.-Y. Xu, Y. Xia, Y. S. Hor, D. Qian, A. V. Fedorov, H. Lin, A. Bansil, R. J. Cava and M. Z. Hasan

Nature Physics 6, 855 (2010)


  NbSe2  
  NbSe2  
  Demonstration of a Fully Bulk Insulating (Intrinsic) Topological Insulator
 
 
Observation of topological surface state quantum Hall effect in an intrinsic three-dimensional topological insulator.
Published in Y. Xu, I. Miotkowski, C. Liu, J. Tian, H. Nam, N. Alidoust, J. Hu, C.-K. Shih, M. Z. Hasan and Y. P. Chen,
Nature Physics 10, 956 (2014).

 
 
Anomalous transport and chiral charge order in kagome superconductor CsV3Sb5
Zhiwei Wang, Yu-Xiao Jiang, Yongkai Li, Jia-Xin Yin, Guan-Yong Wang, Hai-Li Huang, Jinjin Liu, Peng Zhu, Nana Shumiya, Md Shafayat Hossain, Hongxiong Liu, Youguo Shi, Junxi Duan, Xiang Li, Guoqing Chang, Pengcheng Dai, Hao Zheng, Jinfeng Jia, M. Zahid Hasan, Yugui Yao

arXiv:2105.04542 (2021)

Weyl, Dirac and high-fold chiral fermions in topological quantum matter

M. Zahid Hasan, Guoqing Chang, Ilya Belopolski, Guang Bian, Su-Yang Xu, Jia-Xin Yin

Nature Reviews Materials (2021)

Discovery of unconventional chiral charge order in the normal state of 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

arXiv:2012.15709

Intriguing magnetism of the topological kagome magnet TbMn_6Sn_6

C. Mielke III, Wenlong Ma, V. Pomjakushin, O. Zaharko, X. Liu, J. -X. Yin, S. S. Tsirkin, T. A. Cochran, M. Medarde, V. Poree, D. Das, C. N. Wang, J. Chang, T. Neupert, A. Amato, S. Jia, M. Z. Hasan, H. Luetkens, Z. Guguchia

arXiv:2101.05763

Nodeless kagome superconductivity in LaRu3Si2

C. Mielke III, Y. Qin, J. -X. Yin, H. Nakamura, D. Das, K. Guo, R. Khasanov, J. Chang, Z. Q. Wang, S. Jia, S. Nakatsuji, A. Amato, H. Luetkens, G. Xu, Z. M. Hasan, Z. Guguchia

Phys. Rev. Materials 5, 034803 (2021)