High-spin superconductivity in topological half-Heusler semimetals
In all known fermionic superfluids, Cooper pairs are composed of spin-1/2 quasi-particles that
pair to form either spin-singlet or spin-triplet bound states. The "spin" of a Bloch electron, however, is fixed by the
symmetries of the crystal and the atomic orbitals from which it is derived, and in some cases can behave as if it were a spin-3/2 particle. The superconducting state of such a system allows pairing states to form beyond triplet, with higher spin quasi-particles combining to form quintet or even septet pairs. After reviewing experimental evidence for high-spin pairing in the exotic superconducting state of the half-Heusler compound YPtBi, I will introduce our recent work elucidating the influence of spin-orbit coupling on both the normal and superconducting states of this system.