Theoretical Insights into Non-Arrhenius Behaviors of Thermal Vacancies in Anharmonic Crystals

Abstract

Vacancies are prevalent point defects in crystals, but their thermal responses are elusive. Herein, we formulate a simple theoretical model to shed light on the vacancy evolution during heating. Vibrational excitations are thoroughly investigated via moment recurrence techniques in quantum statistical mechanics. On that basis, we carry out numerical analyses for Ag, Cu, and Ni with the Sutton-Chen many-body potential. Our results reveal that the well-known Arrhenius law is insufficient to describe the proliferation of vacancies. Specifically, anharmonic effects lead to a strong nonlinearity in the Gibbs energy of vacancy formation. Our physical picture is well supported by previous simulations and experiments.

Accepted for publication in Physical Chemistry Chemical Physics 2022

References in corpus (4)

• Machine-learning interatomic potentials for materials science
• Diffusion quantum Monte Carlo study of the equation of state and point defects in aluminum
• Anharmonic Thermodynamics of Vacancies Using a Neural Network Potential
• Breakdown of the Arrhenius Law of the Temperature Dependent Vacancy Concentration in fcc-Lanthanum

Cited by in corpus (1)

• Theoretical predictions of melting behaviors of hcp iron up to 4000 GPa