Unconventional localization phenomena in a spatially non-uniform disordered material

TL;DR

This paper reveals unconventional electronic localization behavior in a non-uniform disordered material, showing a transition from localization to delocalization with increasing disorder, contrary to traditional models.

Contribution

It introduces the concept of localization-to-delocalization transition in a spatially non-uniform disordered system, supported by analysis of flux response and eigenstates.

Findings

Maximum current amplitude decreases with weak disorder

Maximum current amplitude increases with strong disorder

Evidence of localization-delocalization transition

Abstract

A completely opposite behavior of electronic localization is revealed in a spatially non-uniform disordered material compared to the traditional spatially uniform disordered one. This fact is substantiated by considering an order-disorder separated (ODS) nanotube and studying the response of non-interacting electrons in presence of magnetic flux. We critically examine the behavior of flux induced energy spectra and circular current for different band fillings, and it is observed that maximum current amplitude (MCA) gradually decreases with disorder strength for weak disorder regime, while surprisingly it (MCA) increases in the limit of strong disorder suppressing the effect of disorder, resulting higher conductivity. This is further confirmed by investigating Drude weight and exactly same anomalous feature is noticed. It clearly gives a hint that localization-to-delocalization transition (LTD) is expected upon the variation of disorder strength which is justified by analyzing the nature of different eigenstates. Our analysis may give some significant inputs in analyzing conducting properties of different doped materials.