Multipolar superconductivity in Luttinger semimetals

TL;DR

This paper explores how multipolar orderings in Luttinger semimetals can give rise to topological superconducting phases, with specific focus on the quadrupolar Kondo semimetal PrBi and potential experimental probes.

Contribution

It introduces the concept of multipolar superconductivity in Luttinger semimetals and analyzes their topological properties, especially in the context of the quadrupolar Kondo system PrBi.

Findings

Multipolar ordering leads to diverse topological superconducting phases.

Derived a microscopic model for quadrupolar Kondo semimetal PrBi.

Proposed experimental methods to detect topological quasiparticles.

Abstract

Topological superconductivity in multiband systems has received much attention due to a variety of possible exotic superconducting order parameters as well as non-trivial bulk and surface states. While the impact of coexisting magnetic order on superconductivity has been studied for many years, such as ferromagnetic superconductors, the implication of coexisting multipolar order has not been explored much despite the possibility of multipolar hidden order in a number of $f$-electron materials. In this work, we investigate topological properties of multipolar superconductors that may arise when quadrupolar local moments are coupled to conduction electrons in the multiband Luttinger semimetal. We show that the multipolar ordering of local moments leads to various multipolar superconductors with distinct topological properties. We apply these results to the quadrupolar Kondo semimetal system, PrBi, by deriving the microscopic multipolar Kondo model and examining the possible superconducting order parameters. We also discuss how to experimentally probe the topological nature of the Bogoliubov quasiparticles in distinct multipolar superconductors via doping and external pressure, especially in the context of PrBi.