Microscopic observation of two-level systems in a metallic glass model

TL;DR

This study uses computational models to identify and analyze microscopic tunneling defects in metallic glasses, revealing their behavior and density changes with glass stability, aligning with experimental data.

Contribution

It provides a detailed microscopic analysis of tunneling defects in metallic glasses using advanced simulation techniques, expanding understanding of their low-temperature properties.

Findings

Tunneling defect density decreases with increased glass stability.

Density of defects near the glass transition temperature matches experimental observations.

Identified microscopic nature of defects in metallic glass models.

Abstract

The low-temperature quasi-universal behavior of amorphous solids has been attributed to the existence of spatially-localized tunneling defects found in the low-energy regions of the potential energy landscape. Computational models of glasses can be studied to elucidate the microscopic nature of these defects. Recent simulation work has demonstrated the means of generating stable glassy configurations for models that mimic metallic glasses using the swap Monte Carlo algorithm. Building on these studies, we present an extensive exploration of the glassy metabasins of the potential energy landscape of a variant of the most widely used model of metallic glasses. We carefully identify tunneling defects and reveal their depletion with increased glass stability. The density of tunneling defects near the experimental glass transition temperature appears to be in good agreement with experimental measurements.