Establishing the Platform of Quasi-one-dimensional Topological Insulators with Emergent Functionalities

This program aims at addressing some of the major challenges facing three-dimensional (3D) and 2D topological insulators (TIs), by establishing the physics platform and materials database of various quasi-1D topological materials with emergent functionalities. Our goals are: (1). design and optimization of quasi-1D TI candidates; (2). synthesis and characterization of the materials; (3). demonstration of phase transitions between different topological phases by strain and/or temperature; (4). the search for 2D TIs in atomically thin layers of quasi-1D materials.

Synergistic and iterative collaborations have been established among the five team members with strong and diverse expertise in theory and computation, materials synthesis, spin- and angle- resolved photoemission spectroscopy, nanofabrication and quantum transport, and neutron and x-ray scattering. Successful implementation of the program will actualize the potentials offered by quasi-1D materials in the realization and discovery of a variety of topological quantum phases including tuning their topological phase transitions. These advances will ultimately pave the way for the realization of fault-tolerant quantum computing and novel spintronic devices for next-generation information technology.

# Publications

Impact of Electric Field Disorder on Broken-Symmetry States in Ultraclean Bilayer Graphene

F. R. Geisenhof, F. Winterer, A. M. Seiler, J. Lenz, F. Zhang, and R. T. Weitz

Sep 2022

A Three-Stage Magnetic Phase Transition Revealed in Ultrahigh-Quality van der Waals Bulk Magnet CrSBr

W. H. Liu, X. Y. Guo, J. Schwartz, H. C. Xie, N. U. Dhale, S. H. Sung, A. L. N. Kondusamy, X. Q. Wang, H. A. Zhao, D. Berman, R. Hovden, L. Y. Zhao, and B. Lv

Sep 2022

Quantum Cascade of Correlated Phases in Trigonally Warped Bilayer Graphene

A. M. Seiler, F. R. Geisenhof, F. Winterer, K. Watanabe, T. Taniguchi, T. Y. Xu, F. Zhang, and R. T. Weitz

Aug 2022

Uncovering Topological Edge States in Twisted Bilayer Graphene

M. Fortin-Deschenes, R. Pu, Y. F. Zhou, C. Ma, P. Cheung, K. Watanabe, T. Taniguchi, F. Zhang, X. Du, and F. N. Xia

Jul 2022

Evidence of a Room-temperature Quantum Spin Hall Edge State in a Higher-order Topological Insulator

N. Shumiya, M. S. Hossain, J. X. Yin, Z. W. Wang, M. Litskevich, C. Yoon, Y. K. Li, Y. Yang, Y. X. Jiang, G. M. Cheng, Y. C. Lin, Q. Zhang, Z. J. Cheng, T. A. Cochran, D. Multer, X. P. Yang, B. Casas, T. R. Chang, T. Neupert, Z. J. Yuan, S. Jia, H. Lin, N. Yao, L. Balicas, F. Zhang, Y. G. Yao, and M. Z. Hasan

Jul 2022

Intelligent Infrared Sensing Enabled by Tunable Moire Quantum Geometry

C. Ma, S. F. Yuan, P. Cheung, K. Watanabe, T. Taniguchi, F. Zhang, and F. N. Xia

Apr 2022

Nonsymmorphic Symmetry-protected Band Crossings in a Square-net Metal PtPb4

H. Wu, A. M. Hallas, X. C. Cai, J. W. Huang, J. S. Oh, V. Loganathan, A. Weiland, G. T. McCandless, J. Y. Chan, S. K. Mo, D. H. Lu, M. Hashimoto, J. Denlinger, R. J. Birgeneau, A. H. Nevidomskyy, G. Li, E. Morosan, and M. Yi

Mar 2022

New Layered Quaternary BaCu6Sn2As4-x and BaCu6Sn2P4-x phases: Crystal Growth and Physical Properties

H. L. Wu, S. Li, X. Q. Wang, S. Kwon, W. H. Liu, G. A. Ofenstein, M. J. Kim, and B. Lv

Feb 2022

Reproducibility in the Fabrication and Physics of Moire Materials

C. N. Lau, M. W. Bockrath, K. F. Mak, and F. Zhang

Feb 2022

Gate-Tunable Transport in Quasi-One-Dimensional a-Bi4I4 Field Effect Transistors

Y. L. Liu, R. Y. Chen, Z. N. Zhang, M. Bockrath, C. N. Lau, Y. F. Zhou, C. H. Yoon, S. Li, X. Y. Liu, N. Dhale, B. Lv, F. Zhang, K. Watanabe, T. Taniguchi, J. W. Huang, M. Yi, J. S. Oh, and R. J. Birgeneau

Jan 2022

Quantum Anomalous Hall Octet Driven by Orbital Magnetism in Bilayer Graphene

F. R. Geisenhof, F. Winterer, A. M. Seiler, J. Lenz, T. Y. Xu, F. Zhang, and R. T. Weitz

Oct 2021

Transport Anomalies in the Layered Compound BaPt4Se6

S. Li, Y. C. Zhang, H. L. Wu, H. F. Zhai, W. H. Liu, D. P. Petit, J. S. Oh, J. Denlinger, G. T. McCandless, J. Y. Chan, R. J. Birgeneau, G. Li, M. Yi, and B. Lv

Sep 2021

Room-Temperature Topological Phase Transition in Quasi-One-Dimensional Material Bi4I4

J. W. Huang, S. Li, C. Yoon, J. S. Oh, H. Wu, X. Y. Liu, N. Dhale, Y. F. Zhou, Y. C. Guo, Y. C. Zhang, M. Hashimoto, D. H. Lu, J. Denlinger, X. Q. Wang, C. N. Lau, R. J. Birgeneau, F. Zhang, B. Lv, and M. Yi

Aug 2021

New Verbeekite-type Polymorphic Phase and Rich Phase Diagram in the PdSe2-xTex System

W. H. Liu, M. R. Osanloo, X. Q. Wang, S. Li, N. Dhale, H. L. Wu, M. L. Van de Put, S. Tiwari, W. G. Vandenberghe, and B. Lv

Jul 2021

Engineering Symmetry Breaking in 2D Layered Materials

L. J. Du, T. Hasan, A. Castellanos-Gomez, G. B. Liu, Y. G. Yao, C. N. Lau, and Z. P. Sun

Feb 2021

Enhanced Superconductivity in the Se-substituted 1T-PdTe2

W. H. Liu, S. Li, H. L. Wu, N. Dhale, P. Koirala, and B. Lv

Jan 2021

Canted Antiferromagnetism in the Quasi-one-dimensional Iron Chalcogenide BaFe2Se4

X. Y. Liu, K. M. Taddei, S. Li, W. H. Liu, N. Dhale, R. Kadado, D. Berman, C. Dela Cruz, and B. Lv

Nov 2020

Emergent Quantum Materials

C. N. Lau, F. N. Xia, and L. Y. Cao

Sep 2020

Line Up for High-temperature Majoranas

Z. Q. Bao and F. Zhang

Aug 2020

Moire Band Topology in Twisted Bilayer Graphene

C. Ma, Q. Y. Wang, S. Mills, X. L. Chen, B. C. Deng, S. F. Yuan, C. Li, K. Watanabe, T. Taniguchi, X. Du, F. Zhang, and F. N. Xia

Jul 2020

Novel Polymorphic Phase of BaCu2As2: Impact of Flux for New Phase Formation in Crystal Growth

H. L. Wu, S. Li, Z. Wu, X. Q. Wang, G. A. Ofenstein, S. Kwon, M. J. Kim, P. C. W. Chu, and B. Lv

Jul 2020

Zero-bias Conductance Peak in Dirac Semimetal-superconductor Devices

W. Yu, R. Haenel, M. A. Rodriguez, S. R. Lee, F. Zhang, M. Franz, D. I. Pikulin, and W. Pan

Jul 2020

Strong Mid-infrared Photoresponse in Small-twist-angle Bilayer Graphene

B. C. Deng, C. Ma, Q. Y. Wang, S. F. Yuan, K. Watanabe, T. Taniguchi, F. Zhang, and F. N. Xia

Jun 2020

Unconventional Valley-dependent Optical Selection Rules and Landau Level Mixing in Bilayer Graphene

L. Ju, L. Wang, X. Li, S. Moon, M. Ozerov, Z. G. Lu, T. Taniguchi, K. Watanabe, E. Mueller, F. Zhang, D. Smirnov, F. Rana, and P. L. McEuen

Jun 2020

Crystal Structure and Electronic Properties of New Compound Zr6.5Pt6Se19

H. L. Wu, H. F. Zhai, S. Li, M. Sorolla, G. T. McCandless, D. P. Petit, J. L. Y. Chan, and B. Lv

May 2020

Composite Dirac Semimetals

Z. M. Zhu, Z. M. Yu, W. K. Wu, L. F. Zhang, W. Zhang, F. Zhang, and S. Y. A. Yang

Oct 2019

# Research Highlights

Discovery of Tunable Quantum Anomalous Hall Octet

Fan Zhang (University of Texas at Dallas)

Special Achievements of PI Zhang’s Students

Fan Zhang, the University of Texas at Dallas

New Topology & Tunable Superconductivity in a-Bi4I4

R.J. Birgeneau (Berkeley), C. N. Lau (Ohio St.),B. Lv, F. Zhang (UT-Dallas), M. Yi (Rice)

Evidence of a Room-temperature Quantum Spin Hall Edge State in a Higher-order Topological Insulator

Fan Zhang (University of Texas at Dallas)