Effect of spin fluctuations on Tc from density-functional theory for superconductors

TL;DR

This paper extends density functional theory for superconductors by incorporating spin fluctuations to study their impact on critical temperature (Tc) in simple metals and niobium under pressure.

Contribution

It introduces a method to include transverse spin fluctuations in SCDFT and assesses their effect on Tc across different materials and pressures.

Findings

Spin fluctuations can significantly influence Tc in simple metals.

The method effectively models pressure-dependent Tc in niobium.

Spin fluctuations are treated within the random phase approximation.

Abstract

The transverse spin fluctuations are introduced to the density functional theory for superconductors (SCDFT). Paramagnons are treated within the random phase approximation and assumed to be the same for the normal and superconducting state. The effect of spin fluctuations on Tc is studied for a few simple metals at ambient pressure and niobium at several pressures up to 80 GPa.