Title: Strain-tuned topological phase transition in ZrTe5
Speaker: Jiun-Haw Chu, University of Washington
Abstract: Band insulators with time reversal symmetry can be classified into normal insulators (NI), weak topological insulators (WTI) and strong topological insulators (STI) based on their Z2 topological indices. Changing Z2 indices requires closing and reopening the bandgap, and topologically distinct insulating phases are separated by a gapless Dirac or Weyl semimetal phase. The van der Waal layered material ZrTe5 is a prototypical example that the emergence of massive 3D Dirac fermions is due to its proximity to the STI-WTI phase boundary. In this talk, I will demonstrate that a STI-WTI topological phase transition can be induced by applying uniaxial stress to ZrTe5, and make the case that the in-situ tunable strain is a powerful to study and control topological materials. In addition, due to the low carrier density in this material, the lowest Landau level can be reached within a few tesla of magnetic field. I will describe the unusual angle dependent magnetotransport behavior in the quantum limit magnetic fields.
Host: Paglione
Refreshments Served at 1:30pm John S Toll Physics Bldg Room 1117