Coarse grained Density Functional theory of order-disorder phase transitions in metallic alloys

TL;DR

This paper introduces a quantum mechanical, coarse-grained density functional theory approach combined with Monte Carlo simulations to effectively model order-disorder phase transitions in metallic alloys, capturing both electronic and atomic effects.

Contribution

It presents a novel, fully quantum mechanical method using a coarse-grained DFT and Monte Carlo techniques to study phase transitions in metallic alloys, bridging a gap in existing high-temperature theories.

Findings

Accurately describes order-disorder phase transitions in CuZn and Ni3V alloys.

Provides thermodynamic and electronic structure insights at finite temperatures.

Supports the validity of the quantum approach for metallic systems.

Abstract

The technological performances of metallic compounds are largely influenced by atomic ordering. Although there is a general consensus that successful theories of metallic systems should account for the quantum nature of the electronic glue, existing non-perturbative high-temperature treatments are based on effective classical atomic Hamiltonians. We propose a solution for the above paradox and offer a fully quantum mechanical, though approximate, theory that on equal footing deals with both electrons and ions. By taking advantage of a coarse grained formulation of the density functional theory [Bruno et al., Phys. Rev. B 77, 155108 (2008)] we develop a MonteCarlo technique, based on an ab initio Hamiltonian, that allows for the efficient evaluation of finite temperature statistical averages. Calculations of the relevant thermodynamic quantities and of the electronic structures for CuZn and Ni$_3$V support that our theory provides an appropriate description of order-disorder phase transitions.