Effective bands and band-like electron transport in amorphous solids

TL;DR

This paper introduces a first-principles method to understand how electrons can exhibit band-like transport in amorphous solids, specifically demonstrating this in amorphous In2O3, and explaining the physical mechanisms behind electron delocalization.

Contribution

The study develops a novel first-principles approach combining a new amorphous state representation with advanced electronic structure theory to analyze electron transport in disordered materials.

Findings

Successfully reproduces band-like conduction in amorphous In2O3

Identifies physical origins of electron delocalization in amorphous solids

Demonstrates disorder-limited mobility consistent with experiments

Abstract

The localization of electrons caused by atomic disorder is a well-known phenomenon. However, what circumstances allow electrons to remain delocalized and retain band-like characteristics even when the crystal structure is completely absent, as found in certain amorphous solids, is less well understood. To probe this phenomenon, we developed a fully first-principles description of the electronic structure and charge transport in amorphous solids by combining a novel representation of the amorphous state with the state-of-the-art many-body (QSGW) electronic structure theory. Using amorphous In2O3 as an example, we demonstrate the accuracy of our approach in reproducing the band-like nature of the conduction electrons as well as their disorder-limited mobility. Our approach reveals the physical origins responsible for the electron delocalization and the survival of the band dispersions despite the absence of long-range order.