Organic glasses: cluster structure of the random energy landscape

TL;DR

This paper models the energy landscape in organic glasses as a spatially correlated Gaussian field, analyzing cluster structures and the impact of correlations and electrodes on disorder properties.

Contribution

It introduces a method to estimate cluster size distributions using the average field distribution and explores the effects of spatial correlations and electrodes on energetic disorder.

Findings

Distribution width depends strongly on spatial correlations.

Average field distribution can estimate deep cluster behavior.

Electrodes significantly modify disorder properties near surfaces.

Abstract

An appropriate model for the random energy landscape in organic glasses is a spatially correlated Gaussian field. We calculated the distribution of the average value of a Gaussian random field in a finite domain. The results of the calculation demonstrate a strong dependence of the width of the distribution on the spatial correlations of the field. Comparison with the simulation results for the distribution of the size of the cluster indicates that the distribution of an average field could serve as a useful tool for the estimation of the asymptotic behavior of the distribution of the size of the clusters for "deep" clusters where value of the field on each site is much greater than the rms disorder. We also demonstrate significant modification of the properties of energetic disorder in organic glasses at the vicinity of the electrode.