Level spacing statistics of disordered finite superlattices spectra and motional narrowing as a random matrix theory effect

TL;DR

This paper investigates the spectral properties of disordered superlattices using random matrix theory, revealing a motional narrowing effect that influences level spacing distributions and miniband behavior.

Contribution

It introduces a novel analysis of level repulsion suppression mechanisms in disordered superlattices within a random matrix framework.

Findings

Identification of three level repulsion suppression mechanisms.

Observation of motional narrowing effect in disordered superlattices.

Analysis of level spacing distribution evolution within minibands.

Abstract

In the present work the problem of coupled disordered quantum wells is addressed in a random matrix theory framework. The quantum wells are short repulsive binary alloys embeded by ordered barriers and show well defined quantized levels as a consequence of spatial confinement. Finite disordered superlattices may show both diffusive-like and localized minibands. Three different level repulsion suppression mechanisms are discussed by analysing the evolution of nearest-level-spacing distribution function within each superlattice miniband. The present numerical results show a motional narrowing effect, which is in fact a consequence of the random matrix theory.