"Cornering" the electron in a topological insulator via periodic driving

by Dr. Ranjani Seshadri

BGU

at Condensed Matter Seminar

Mon, 25 Oct 2021, 11:30
Sacta-Rashi Building for Physics (54), room 207

Abstract

In this talk, I will be discussing a relatively new entrant to the field of topology
in condensed matter physics called higher-order topological insulators (HOTIs).
Usually, TIs in two dimensions are known to host robust one-dimensional edge
modes. These are related to the bulk properties via a topological invariant such
as the Chern number. However, in HOTIs, there are zero-dimensional corner
modes. These are confined to the vertices of a sample. In this work, a variant
of the well-known Bernevig-Hughes-Zhang model of a two-dimensional TI is
used to construct a two-dimensional HOTI. This equilibrium model has both
topological and non-topological phases. By applying a periodic external perturbation,
one can manipulate these topological phases and change the properties of said
corner modes. We try to understand the bulk-boundary correspondence associated
with such corner states.

Reference: R. Seshadri, A. Dutta, and D. Sen, Phys. Rev. B 100, 115403

Created on 14-10-2021 by Meidan, Dganit (dganit)
Updaded on 22-10-2021 by Meidan, Dganit (dganit)