Non-Gaussian Resistance Fluctuations in Disordered Materials

TL;DR

This study investigates resistance fluctuation distributions in disordered thin films, revealing non-Gaussian behavior influenced by disorder level, system size, and bias, with universal features near the conductor-insulator transition.

Contribution

It introduces a resistor network model combined with Monte Carlo simulations to analyze resistance fluctuations across different disorder regimes and bias conditions.

Findings

Resistance fluctuations deviate from Gaussian distribution depending on disorder and size.

Strongly disordered systems near the critical point follow the universal Bramwell-Holdsworth-Pinton distribution.

Non-Gaussian behavior persists with increasing system size in highly disordered regimes.

Abstract

We study the distribution of resistance fluctuations of conducting thin films with different levels of internal disorder. The film is modeled as a resistor network in a steady state determined by the competition between two biased processes, breaking and recovery of the elementary resistors. The fluctuations of the film resistance are calculated by Monte Carlo simulations which are performed under different bias conditions, from the linear regime up to the threshold for electrical breakdown. Depending on the value of the external current, on the level of disorder and on the size of the system, the distribution of the resistance fluctuations can exhibit significant deviations from Gaussianity. As a general trend, a size dependent, non universal distribution is found for systems with low and intermediate disorder. However, for strongly disordered systems, close to the critical point of the conductor-insulator transition, the non-Gaussianity persists when the size is increased and the distribution of resistance fluctuations is well described by the universal Bramwell-Holdsworth-Pinton distribution.