Multipolar superconductivity in Luttinger semimetals

Topological superconductivity in multiband systems has received much attention due to a variety of possible exotic superconducting order parameters as well as nontrivial bulk and surface states. While the impact of coexisting magnetic order on superconductivity, such as ferromagnetic superconductors, has been studied for many years, 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.