[Physics-grads-open] Condensed Matter Seminar, May 31st

[Heather Mcdermott]

[cid:18627e3ec714cff311]

Condensed Matter Seminar








Exchange-bias-driven and Interaction-driven Quantum Anomalous Hall Effect in Topological Insulator Heterostructures


Dr. Chao-Xing Liu


Department of Physics, Pennsylvania State University, University Park


Abstract: Quantum anomalous Hall (QAH) state is a magnetic topological state with zero longitudinal resistance and quantized Hall resistance, occurring in the absence of external magnetic fields due to spontaneously broken time-reversal symmetry. The QAH effect has now been realized in several different classes of two-dimensional materials, including magnetically (Cr or V) doped (Bi,Sb)2Te3, MnBi2Te4, and Moire materials of graphene and transition metal dichalcogenides. Despite of the impressive progress, the temperature at which the QAH effect is observed is still limited to a few Kelvins. Two general approaches are expected to enhance this critical temperature [1]: (1) high-quality heterostructures between topological insulators and high Curie temperature ferromagnetic insulator; and (2) new Moire systems. In this talk, I will describe our theoretical efforts along these directions. (1) The strong exchange bias between MnBi2Te4 and CrI3 can give rise to the electrically tunable QAH effect in MnBi2Te4/CrI3 heterostructure [2]. (2) Isolated topologically non-trivial Moire mini-bands can be formed for a topological insulator film under a Moire superlattice and Coulomb interaction can drive this system into the QAH state when the non-trivial Moire mini-band is half filled.
[1] Cui-Zu Chang, Chao-Xing Liu, Allan H. MacDonald, Colloquium: Quantum anomalous Hall effect, Reviews of Modern Physics, 2023, 95(1): 011002.
[2] Fu H, Liu C X, Yan B. Exchange bias and quantum anomalous Hall effect in the MnBi2Te4/CrI3 heterostructure[J]. Science advances, 2020, 6(10): eaaz0948.
[3] Z2-Nontrivial Moiré Minibands and Interaction-Driven Quantum Anomalous Hall Insulators in Topological Insulator Based Moiré Heterostructures, Kaijie Yang, Zian Xu, Yanjie Feng, Frank Schindler, Yuanfeng Xu, Zhen Bi, B. Andrei Bernevig, Peizhe Tang, Chao-Xing Liu, arXiv:2304.09907, 2023.



Wednesday, May 31st, 2023

4:00 PM in the Reading Room (Physics 3035)



Heather McDermott
Travel & Event Coordinator
Physics & Astronomy Dept.
University of California Riverside
Ph: 951-827-6169
heatherm at ucr.edu<mailto:heatherm at ucr.edu>

AVAILABLE VIA ZOOM
FOR VIRTUAL OFFICE
HOURS AT:
https://ucr.zoom.us/my/heathermcdermott



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