Tunnelling between edge states of a 2D topological insulator and a Fermi liquid lead through a quantum dot

Department of Physcis, Hong Kong University of Science and Technology - Hong Kong, PRC

^a cseng@wisc.edu

Received: 6 August 2011
Accepted: 27 October 2011

Abstract

In this paper we study a non-equilibrium resonant tunnelling problem where a non-interacting quantum dot is connected to two leads, one being the edge of an interacting 2D topological insulator (Luttinger liquid) and the other being a usual Fermi liquid. We show that the current passing through the system can be expressed in terms of a non-equilibrium local single-particle Green's function of the Luttinger liquid lead which can be analysed using standard bosonization-renormalization group (RG) technique. In particular, some exact results can be extracted in the small-bias limit with repulsive electron-electron interaction. A simple formula which captures the qualitative feature of the I-V relation over the whole temperature and voltage bias range is proposed and studied.