Junwei Liu Seminar


Lecture Details

12:30 pm - 1:15 pm, plus Q & A
SERC Building, room 703
Title: Topological Phases in Transition Metal Chalcogenides

SpeakerJunwei Liu, Hong Kong University of Science and Technology, Dept of Physics

Remote Viewers:
For individuals who will not be on Temple's campus, Dr. Liu' lecture can be accessed through WebEx.  The meeting number is: 646 010 832




The discovery of quantum spin Hall effect engendered a new chapter of topological materials research in condensed matter physics and materials science. In this talk, I will introduce some of our recent theoretical works about the topological phases in 2D and 3D transition metal chalcogenides. We predict monolayer MX2 (M=Mo, W; X=S, Se, Te) of 1T’ structure could realize quantum spin Hall insulator. Moreover, their topology can be easily tuned by external electric field, which motivated us to propose a new type of transistor, called topological field transistor. More recently, we found another new class of transition metal chalcogenides MM’Te4 (M=Nb, Ta; M’=Ir, Rh) could be quantum spin Hall insulators in 2D and Weyl semimetals in 3D. I will also discuss some recent transport, ARPES and STM experiments on monolayer WTe2, where many of the observations are consistent with monolayer WTe2 being a 2D TI.
[1] X. Qian, J. Liu, L. Fu, J. Li,Science 346, 1344 (2014)
[2] J. Liu, H. Wang, C. Fang, L. Fu, X. Qian, Nano Lett. 17 467-475 (2017)


Junwei Liu has a broad interest in condensed matter physics, from the traditional phenomena like ferroelectricity to the exotic topological phases like quantum spin Hall insulators. Currently, his research mainly focuses on two parts: 1) the novel topological phases of matter, especially the symmetry-related topological phases, and their material realizations and experimental signatures; 2) applications of advanced machine learning techniques in physics, especially the combination of machine learning techniques and quantum Monte Carlo simulations.