Suppresion of Bloch oscillations by weak disorder in semiconductor superlattices

TL;DR

This paper models how weak disorder causes rapid dephasing of Bloch oscillations in semiconductor superlattices, aligning with experimental results and predicting disorder-dependent oscillation lifetimes.

Contribution

It introduces a simple model demonstrating that small well width fluctuations lead to fast dephasing, independent of electric field, and matches experimental observations.

Findings

Disorder causes rapid dephasing of Bloch oscillations.

Oscillation lifetime depends on disorder level, not electric field.

Model agrees well with recent experimental data.

Abstract

We investigate the dephasing dynamics of Bloch oscillations in semiconductor superlattices by means of a very simple model including disorder and applied electric fields. A thorough numerical study of our model allows us to claim that small, unintentional well width fluctuations can be responsible for fast dephasing of Bloch oscillations at low temperatures. We show that the lifetime of Bloch oscillations is controlled by a characteristic time which depends on the degree of disorder and is independent of the electric field. This result is further supported by the excellent agreement between our model calculations and several recent experiments, and leads to specific new predictions.