Enhanced Electronic Transport in Disordered Hyperuniform Two-Dimensional Amorphous Silica

TL;DR

This paper reports the discovery of disordered hyperuniformity in 2D amorphous silica, revealing enhanced electronic transport properties and a transition toward metallic behavior due to unique topological constraints.

Contribution

It is the first to identify disordered hyperuniformity in atomic-scale 2D materials and links this state to improved electronic conduction.

Findings

Disordered hyperuniformity observed in 2D amorphous silica.

DHU leads to near-complete closure of the electronic band gap.

Material exhibits metallic behavior due to DHU state.

Abstract

Disordered hyperuniformity (DHU) is a recently proposed new state of matter, which has been observed in a variety of classical and quantum many-body systems. DHU systems are characterized by vanishing infinite-wavelength density fluctuations and are endowed with unique novel physical properties. Here we report the first discovery of disordered hyperuniformity in atomic-scale 2D materials, i.e., amorphous silica composed of a single layer of atoms, based on spectral-density analysis of high-resolution transmission electron microscope images. Subsequent simulations suggest that the observed DHU is closely related to the strong topological and geometrical constraints induced by the local chemical order in the system. Moreover, we show via large-scale density functional theory calculations that DHU leads to almost complete closure of the electronic band gap compared to the crystalline counterpart, making the material effectively a metal. This is in contrast to the conventional wisdom that disorder generally diminishes electronic transport and is due to the unique electron wave localization induced by the topological defects in the DHU state.