Stochastic path-integral approach for predicting the superconducting temperatures of anharmonic solids

TL;DR

This paper introduces a stochastic path-integral method to accurately predict superconducting transition temperatures in anharmonic solids, improving upon traditional harmonic approximations and aligning better with experimental data.

Contribution

It generalizes the stochastic path-integral formalism for anharmonic solids and implements it for ab initio calculations, providing more accurate superconducting temperature predictions.

Findings

Accurately predicts superconducting temperatures for metallic deuterium.

Shows anharmonicity suppresses superconductivity in hydrogen sulfide.

Yields transition temperatures closer to experiments than harmonic methods.

Abstract

We develop a stochastic path-integral approach for predicting the superconducting transition temperatures of anharmonic solids. By defining generalized Bloch basis, we generalize the formalism of the stochastic path-integral approach, which is originally developed for liquid systems. We implement the formalism for ab initio calculations using the projector augmented-wave method, and apply the implementation to estimate the superconducting transition temperatures of metallic deuterium and hydrogen sulfide. For metallic deuterium, which is approximately harmonic, our result coincides well with that obtained from the standard approach based on the harmonic approximation and the density functional perturbation theory. For hydrogen sulfide, we find that anharmonicity strongly suppresses the predicted superconducting transition temperature. Compared to the self-consistent harmonic approximation approach, our approach yields a transition temperature closer to the experimentally observed one.