Alternative approach to computing transport coefficients: application to conductivity and Hall coefficient of hydrogenated amorphous silicon

TL;DR

This paper presents a new theoretical framework for calculating transport coefficients in complex materials, successfully addressing longstanding discrepancies in amorphous silicon and extending to amorphous polyaniline.

Contribution

The authors develop a novel formalism that accounts for localized and extended states, improving the accuracy of transport property predictions in disordered materials.

Findings

Resolved conductivity and Hall mobility discrepancies in amorphous silicon.

Identified localized states as the cause of Hall sign anomaly.

Extended the method to compute AC conductivity in amorphous polyaniline.

Abstract

We introduce a theoretical framework for computing transport coefficients for complex materials. As a first example, we resolve long-standing inconsistencies between experiment and theory pertaining to the conductivity and Hall mobility for amorphous silicon and show that the Hall sign anomaly is a consequence of localized states. Next, we compute the AC conductivity of amorphous polyanaline. The formalism is applicable to complex materials involving defects and band-tail states originating from static topological disorder and extended states. The method may be readily integrated with current \textit{ab initio} methods.