Efficient Selfconsistent Calculations of Multiband Superconductivity in UPd$_2$Al$_3$

TL;DR

This paper introduces an efficient computational method for multiband superconductivity and applies it to UPd$_2$Al$_3$, revealing that the superconductor's gap symmetry is d-wave with nodes positioned to maximize distance from high-density regions.

Contribution

The paper presents a new computational approach combining realistic pairing potentials with density functional theory to study multiband superconductivity.

Findings

Superconducting gap in UPd$_2$Al$_3$ exhibits d-wave symmetry.

Nodes in the gap are positioned to maximize distance from high-density areas.

Method efficiently predicts gap symmetry in complex superconductors.

Abstract

An efficient physically motivated computational approach to multiband superconductivity is introduced and applied to the study of the gap symmetry in a heavy-fermion, UPd$_2$Al$_3$. Using realistic pairing potentials and accurate energy bands that are computed within density functional theory, self-consistent calculations demonstrate that the only accessible superconducting gap with nodes exhibits d-wave symmetry in the $A_{1g}$ representation of the $D_{6h}$ point group. Our results suggest that in a superconductor with gap nodes the prevailing gap symmetry is dictated by the constraint that nodes must be as far as possible from high-density areas.