Superconducting pairing mediated by spin-fluctuations from first principles

TL;DR

This paper develops a parameter-free, ab-initio effective electron-electron interaction model that incorporates spin-fluctuations to predict superconducting properties from first principles.

Contribution

It introduces a novel, parameter-free approach combining many-body perturbation theory and time-dependent density functional theory to model superconducting pairing.

Findings

Results from a two-band electron gas model align with experimental data.

The new functional captures spin-fluctuation mediated pairing.

The approach advances predictive capabilities for superconductors.

Abstract

We present the derivation of an ab-initio and parameter free effective electron-electron interaction that goes beyond the screened RPA and accounts for superconducting pairing driven by spin-fluctuations. The construction is based on many body perturbation theory and relies on the approximation of the exchange-correlation part of the electronic self-energy within time dependent density functional theory. This effective interaction is included in an exchange correlation kernel for superconducting density functional theory, in order to achieve a completely parameter free superconducting gap equation. First results from applying the new functional to a simplified two-band electron gas model are consistent with experiments.