Theory of Transmission through disordered superlattices

TL;DR

This paper develops a theoretical framework for calculating electron transmission through disordered superlattices, accounting for interface roughness, and demonstrates how transmission data can reveal disorder characteristics.

Contribution

A new theory for transmission in disordered superlattices that incorporates interface roughness averaging and compares Keldysh and Landauer-Büttiker formalisms.

Findings

Transmission is significantly affected by interface roughness.

Wannier-function approximation is accurate near the lowest miniband.

Transmission data can infer disorder scale and size.

Abstract

We derive a theory for transmission through disordered finite superlattices in which the interface roughness scattering is treated by disorder averaging. This procedure permits efficient calculation of the transmission thr ough samples with large cross-sections. These calculations can be performed utilizing either the Keldysh or the Landauer-B\"uttiker transmission formalisms, both of which yield identical equations. For energies close to the lowest miniband, we demonstrate the accuracy of the computationally efficient Wannier-function approximation. Our calculations indicate that the transmission is strongly affected by interface roughness and that information about scale and size of the imperfections can be obtained from transmission data.