Analytical study of non-linear transport across a semiconductor-metal junction

TL;DR

This paper provides an analytical study of non-linear electron transport in a semiconductor-metal junction, focusing on Tamm states, surface Green's functions, and the non-linear current-voltage relationship using Green's function methods.

Contribution

It introduces an analytical approach to model non-linear transport and surface states in a semiconductor-metal junction without requiring numerical regularization.

Findings

Strong non-linearities in interface site occupations due to resonances

Analytical surface Green's function without small imaginary parts

Wave functions for surface states derived

Abstract

In this paper we study analytically a one-dimensional model for a semiconductor-metal junction. We study the formation of Tamm states and how they evolve when the semi-infinite semiconductor and metal are coupled together. The non-linear current, as a function of the bias voltage, is studied using the non-equilibrium Green's function method and the density matrix of the interface is given. The electronic occupation of the sites defining the interface has strong non-linearities as function of the bias voltage due to strong resonances present in the Green's functions of the junction sites. The surface Green's function is computed analytically by solving a quadratic matrix equation, which does not require adding a small imaginary constant to the energy. The wave function for the surface states is given.