## "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 19-10-2021 by Meidan, Dganit (dganit)