AC Response of the Edge States in a Two-Dimensional Topological Insulator Coupled to a Conducting Puddle

TL;DR

This paper investigates how the AC electrical response of edge states in a 2D topological insulator is affected by coupling to a conducting puddle, providing a method to characterize such puddles through response measurements.

Contribution

It introduces a theoretical framework for calculating the AC response of topological insulator edge states coupled to bulk puddles, revealing how this coupling modifies the response.

Findings

Finite corrections to AC response due to puddle coupling

Frequency-dependent response modifications

Parameter extraction method for puddle characteristics

Abstract

We calculate an AC response of the edge states of a two-dimensional topological insulator, which can exchange electrons with a conducting puddle in the bulk of the insulator. This exchange leads to finite corrections to the response of isolated edge states both at low and high frequencies. By comparing these corrections, one may determine the parameters of the puddle.