Stochastic and Mixed Density Functional Theory within the projector augmented wave formalism for the simulation of warm dense matter

TL;DR

This paper introduces stochastic and mixed density functional theory methods within the projector augmented wave formalism to efficiently simulate warm dense matter, improving the description of electrons and scaling behavior.

Contribution

It develops and implements stochastic and mixed DFT approaches within the PAW formalism, addressing scaling issues and enhancing electron modeling in warm dense matter simulations.

Findings

Comparison of DFT approaches on trajectories shows consistency.

Calculations of self-diffusion coefficients for carbon from 1 to 50 eV.

Improved electron description in the PAW formalism.

Abstract

Stochastic and mixed stochastic-deterministic density functional theory (DFT) are promising new approaches for the calculation of the equation-of-state and transport properties in materials under extreme conditions. In the intermediate warm dense matter regime, a state between correlated condensed matter and kinetic plasma, electrons can range from being highly localized around nuclei to delocalized over the whole simulation cell. The plane-wave basis pseudo-potential approach is thus the typical tool of choice for modeling such systems at the DFT level. Unfortunately, the stochastic DFT methods scale as the square of the maximum plane-wave energy in this basis. To reduce the effect of this scaling, and improve the overall description of the electrons within the pseudo-potential approximation, we present stochastic and mixed DFT developed and implemented within the projector augmented wave formalism. We compare results between the different DFT approaches for both single-point and molecular dynamics trajectories and present calculations of self-diffusion coefficients of solid density carbon from 1 to 50 eV.