Study of interface phenomena in a topological-insulator/Mott-insulator heterostructure

TL;DR

This paper theoretically explores the electronic interface states in a heterostructure combining a topological insulator and a Mott insulator, revealing the emergence of heavy-fermion-like states and their properties.

Contribution

It introduces a detailed theoretical analysis of interface phenomena in TI/MI heterostructures using inhomogeneous dynamical mean-field theory, highlighting new mid-gap states.

Findings

Identification of heavy-fermion-like mid-gap states at the interface

Analysis of spatial modulation of quasi-particle weight

Effects of local correlations and electron tunneling on optical properties

Abstract

We theoretically investigate a two-dimensional heterostructure composed of a topological insulator (TI) and a Mott insulator (MI), and clarify what kind of electronic states can be realized at the interface. By using inhomogeneous dynamical mean-field theory, we confirm that the topological edge state penetrating into the MI region induces a heavy-fermion like mid-gap state. We further elucidate the nature of the spatially-modulated quasi-particle weight of the mid-gap state, and discuss the effects of local correlation in the TI region. The optical conductivity and the Drude weight are also computed with changing the electron tunneling near the interface.