Computer investigation of the energy landscape of amorphous silica

TL;DR

This study uses molecular dynamics to explore the energy landscape of amorphous silica, revealing temperature-dependent features and anharmonicities similar to fragile glasses, with a characteristic temperature indicating a transition in basin exploration.

Contribution

It provides a detailed analysis of silica's energy landscape, highlighting the onset of anharmonicities and roughness at a specific temperature, advancing understanding of strong glass formers.

Findings

Identification of a characteristic temperature T_c around 3500K.

Observation of non-harmonic potential energy basin exploration above T_c.

Detection of increased roughness in energy valleys at high temperatures.

Abstract

The multidimensional topography of the collective potential energy function of a so-called strong glass former (silica) is analyzed by means of classical molecular dynamics calculations. Features qualitatively similar to those of fragile glasses are recovered at high temperatures : in particular an intrinsic characteristic temperature $T_c\simeq 3500$K is evidenced above which the system starts to investigate non-harmonic potential energy basins. It is shown that the anharmonicities are essentially characterized by a roughness appearing in the potential energy valleys explored by the system for temperatures above $T_c$.