Benchmark of density functional theory for superconductors in elemental materials

TL;DR

This study systematically benchmarks density functional theory for elemental superconductors, incorporating spin-orbit interaction and spin fluctuations, to accurately predict superconducting transition temperatures and validate the method's broad applicability.

Contribution

Developed a method combining SOI and SF effects in DFT calculations, validated against experimental $T_c$ for elemental superconductors.

Findings

Including SOI and SF reproduces experimental $T_c$ accurately.

SOI has a small effect except for a few elements.

SF reduces $T_c$, especially in transition metals.

Abstract

Systematic benchmark calculations for elemental bulks are presented to validate the accuracy of density functional theory for superconductors. We developed a method to treat the spin-orbit interaction (SOI) together with the spin fluctuation (SF) and examine their effect on the superconducting transition temperature. We found the following results from the benchmark calculations: (1) The calculations, including SOI and SF, reproduce the experimental superconducting transition temperature ($T_c$) quantitatively. (2) The effect by SOI is small excepting a few elements such as Pb, Tl, and Re. (3) SF reduces $T_c$s, especially for the transition metals, while this reduction is too weak to reproduce the $T_c$s of Zn and Cd. (4) We reproduced the absence of superconductivity for alkaline (earth) and noble metals. These calculations confirm that our method can be applied to a wide range of materials and implies a direction for the further improvement of the methodology.