Exchange-Correlation Catastrophe in Cu-Au: A Challenge for Semilocal Density Functional Approximations

Area of Science:

• Materials Science
• Computational Chemistry
• Condensed Matter Physics

Background:

• Semilocal density functional approximations (DFAs) are limited in applicability.
• A previous study questioned the ability of semilocal DFT to accurately calculate alloy formation energies.

Purpose of the Study:

• To investigate the relationship between semilocal DFT formation energies and lattice constant accuracy.
• To determine if semilocal functionals can accurately predict alloy formation energies.

Main Methods:

• Exploration of the underlying physics of semilocal DFT formation energies.
• Analysis of the correlation between lattice constant accuracy and formation energy prediction.

Main Results:

• Semilocal DFT can accurately predict alloy formation energies.
• Accurate lattice constants are linked to reliable formation energy calculations.
• Functionals optimized for alloy constituents also improve formation energy predictions.

Conclusions:

• Semilocal density functional approximations are capable of accurately calculating alloy formation energies.
• The accuracy of lattice constants is a key indicator for the reliability of formation energy predictions.
• Tailored semilocal functionals offer a viable solution for alloy formation energy calculations.