New universal conductance fluctuation of mesoscopic systems in the crossover regime from metal to insulator

TL;DR

This paper presents a theoretical study showing a new universal conductance fluctuation in mesoscopic systems during the metal-insulator crossover, dependent on system symmetry and dimensionality.

Contribution

It identifies a novel universal conductance fluctuation value in the crossover regime for systems with specific symmetries, supported by numerical simulations and theoretical analysis.

Findings

Universal conductance fluctuation reaches a new value in the crossover regime.

Conductance fluctuation depends only on dimensionality and symmetry.

Results suggest a link between fluctuation and metal-insulator transition.

Abstract

We report a theoretical investigation on conductance fluctuation of mesoscopic systems. Extensive numerical simulations on quasi-one dimensional, two dimensional, and quantum dot systems with different symmetries (COE, CUE, and CSE) indicate that the conductance fluctuation can reach a new universal value in the crossover regime for systems with CUE and CSE symmetries. The conductance fluctuation and higher order moments vs average conductance were found to be universal functions from diffusive to localized regimes that depend only on the dimensionality and symmetry. The numerical solution of DMPK equation agrees with our result in quasi-one dimension. Our numerical results in two dimensions suggest that this new universal conductance fluctuation is related to the metal-insulator transition.