Stone-Wales Defects Preserve Hyperuniformity in Amorphous Two-Dimensional Materials

TL;DR

This study demonstrates that introducing Stone-Wales defects into amorphous 2D materials preserves hyperuniformity, revealing a structural transition linked to defect concentration and impacting electronic properties.

Contribution

It provides numerical evidence that Stone-Wales defects maintain hyperuniformity in amorphous 2D materials, identifying a transition between hyperuniformity classes at a specific defect level.

Findings

SW defects preserve hyperuniformity in amorphous 2D materials.

A transition from type-I to type-II hyperuniformity occurs at p ≈ 0.12.

Structural transition influences electronic transport mechanisms.

Abstract

Crystalline two-dimensional (2D) materials such as graphene possess unique physical properties absent in their bulk form, enabling many novel device applications. Yet, little is known about their amorphous counterparts, which can be obtained by introducing the Stone-Wales (SW) topological defects via proton radiation. Here we provide strong numerical evidence that SW defects preserve hyperuniformity in hexagonal 2D materials, a recently discovered new state of matter characterized by vanishing normalized infinite-wavelength density fluctuations, which implies that all amorphous states of these materials are hyperuniform. Specifically, the static structure factor S(k) of these materials possesses the scaling S(k) ~ k^{\alpha} for small wave number k, where 1<=\alpha(p)<=2 is monotonically decreasing as the SW defect concentration p increases, indicating a transition from type-I to type-II hyperuniformity at p ~= 0.12 induced by the saturation of the SW defects. This hyperuniformity transition marks a structural transition from perturbed lattice structures to truly amorphous structures, and underlies the onset of strong correlation among the SW defects as well as a transition between distinct electronic transport mechanisms associated with different hyperuniformity classes.