Density-functional Monte-Carlo simulation of CuZn order-disorder transition

TL;DR

This study uses a combined Monte Carlo and density functional theory approach to simulate the CuZn order-disorder transition, accurately predicting the transition temperature and structural changes consistent with experimental observations.

Contribution

It introduces a novel simulation method integrating DFT with Wang-Landau Monte Carlo to study alloy phase transitions.

Findings

Transition from disordered A2 to ordered B2 structure observed.

Calculated transition temperature near 870 K, close to experimental 750 K.

Entropy, specific heat, and short-range order analyzed as functions of energy.

Abstract

We perform a Wang-Landau Monte Carlo simulation of a Cu0.5Zn0.5 order-disorder transition using 250 atoms and pairwise atom swaps inside a 5 x 5 x 5 BCC supercell. Each time step uses energies calculated from density functional theory (DFT) via the all-electron Korringa-Kohn- Rostoker method and self-consistent potentials. Here we find CuZn undergoes a transition from a disordered A2 to an ordered B2 structure, as observed in experiment. Our calculated transition temperature is near 870 K, comparing favorably to the known experimental peak at 750 K. We also plot the entropy, temperature, specific-heat, and short-range order as a function of internal energy.