Speaker: Liu, I-Lin

Title: Fermi Surface Reconstruction in in MoTe$_2$

Abstract:

T$_d$-MoTe$_2$ has been studied for nontrivial electronic topology because it potentially hosts both type II Weyl semimetal and topological superconductivity states. The Weyl nodes and novel topological surface states were identified by means of high-resolution angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT)\cite; monolayer of T'-MoTe$_2$ has been predicted as 2D topological insulator according to Z$_2$ nontrivial band topology. Furthermore, bulk T'-MoTe$_2$ has just been theoretically predicted as a higher order topological insulator without spin-orbit coupling (SOC) and nodal-line semimetal with monopole nodal-line under weak SOC limit. The study of band structure of T$_d$ and T' becomes important to understand their topological states and corresponding novel quantum phenomenon. It was recently shown that pressure also drives a structural transition between inversion-conserving and breaking phases at a critical pressure coinciding with an abrupt enhancement in superconductivity. Here, we demonstrate directly, how pressure tunes between the different electronic structures that break and preserve inversion symmetry in Shubnikov-de Haas oscillation.

Title: Fermi Surface Reconstruction in in MoTe$_2$

Abstract:

T$_d$-MoTe$_2$ has been studied for nontrivial electronic topology because it potentially hosts both type II Weyl semimetal and topological superconductivity states. The Weyl nodes and novel topological surface states were identified by means of high-resolution angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT)\cite; monolayer of T'-MoTe$_2$ has been predicted as 2D topological insulator according to Z$_2$ nontrivial band topology. Furthermore, bulk T'-MoTe$_2$ has just been theoretically predicted as a higher order topological insulator without spin-orbit coupling (SOC) and nodal-line semimetal with monopole nodal-line under weak SOC limit. The study of band structure of T$_d$ and T' becomes important to understand their topological states and corresponding novel quantum phenomenon. It was recently shown that pressure also drives a structural transition between inversion-conserving and breaking phases at a critical pressure coinciding with an abrupt enhancement in superconductivity. Here, we demonstrate directly, how pressure tunes between the different electronic structures that break and preserve inversion symmetry in Shubnikov-de Haas oscillation.