Spin Susceptibility of a J=3/2 Superconductor

TL;DR

This paper analytically investigates the spin susceptibility of J=3/2 superconductor states with strong spin-orbit coupling, revealing symmetry-dependent isotropy and anisotropy in susceptibility tensor components.

Contribution

It provides a theoretical analysis of spin susceptibility in J=3/2 superconductors, highlighting symmetry effects and tensor anisotropy, which were not previously detailed.

Findings

Susceptibility is isotropic for $A_{1g}$ and $T_{2g}$ states.

Susceptibility is anisotropic for $E_g$ states.

Off-diagonal elements appear in the susceptibility tensor for $T_{2g}$ states.

Abstract

We discuss the spin susceptibility of superconductors in which a Cooper pair consists of two electrons having the angular momentum J=3/2 due to strong spin-orbit interactions. The susceptibility is calculated analytically for pseudospin quintet states in a cubic superconductor within the linear response to a Zeeman field. The susceptibility for $A_{1g}$ symmetry states is isotropic in real space. For $E_g$ and $T_{2g}$ symmetry cases, the results depend sensitively on choices of order parameter. The susceptibility is isotropic for a $T_{2g}$ symmetry state, whereas it becomes anisotropic for an $E_{g} $ symmetry state. We also find in a $T_{2g}$ state that the susceptibility tensor has off-diagonal elements.