Proximity effects in a topological-insulator/Mott-insulator heterostructure

TL;DR

This paper explores how a topological insulator influences a neighboring Mott insulator, revealing that edge states induce mid-gap states and modify electronic properties within the heterostructure, with effects depending on interface tunneling strength.

Contribution

It demonstrates the impact of topological edge states on a correlated Mott insulator using inhomogeneous dynamical mean-field theory, highlighting the emergence of mid-gap states and Dirac-cone splitting.

Findings

Edge states induce mid-gap states in the Mott insulator.

Strong interface tunneling enhances electron mass and splits Dirac cones.

Proximity effects depend on the interface tunneling parameter V.

Abstract

We investigate proximity effects in a correlated heterostructure of a two-dimensional Mott insulator (MI) and a topological insulator (TI) by employing inhomogeneous dynamical mean-field theory. We show that the edge state of the TI induces strongly renormalized mid-gap states inside the MI region, which still have a remnant of the helical energy-spectrum. The penetration of low-energy electrons, which is controlled by the interface tunneling $V$, largely enhances the electron mass inside the MI and also splits a single Dirac-cone at edge sites into the spatially-separated two Dirac-cones in the strong $V$ region.