Efficient, Systematic Estimation of Alloy Free Energy from Special Microscopic States

TL;DR

This paper introduces a novel method to estimate the Helmholtz free energy of substitutional alloys using special microscopic states that depend only on the lattice, enabling efficient and systematic predictions without thermodynamic data.

Contribution

The authors propose a lattice-dependent, thermodynamics-independent approach to calculate free energy in alloys, simplifying and accelerating predictions compared to traditional methods.

Findings

Method provides reasonable predictions above transition temperatures.

Special states are independent of energy and temperature.

Effective for alloys with many-body interactions.

Abstract

For classical discrete systems under constant composition typically refferred to substitutional alloys, we propose calculation method of Helmholtz free energy based on a set of special microscopic states. The advantage of the method is that configuration of the special states are essentially independent of energy and temperature, and they depend only on underlying lattice: The special states can be known a priori without any thermodynamic information, enabling systematic prediction of free energy for multicomponent alloys. We confirm that by comparing to conventional thermodynamic simulation, information about the special states provide reasonable predictive power above order-disorder and phase-separating transition temperature for alloys with many-body (up to 3-body) interactions.