High-spin quasiparticles in topological semimetal YPtBi

Prof. Hyunsoo Kim, Department of Physics, Missouri S&T
Zoom Seminar
Guang Bian

Quasiparticles with total angular momentum greater than j=1/2 can emerge in a solid state with strong spin-orbit interaction. While the existence of such high-spin quasiparticles has been known for decades, their implication has been largely overlooked. The possibility of superconductivity beyond spin-triplet in such solid states attracted substantial attention. In this talk, I will talk about unconventional quantum oscillations and superfluid response in half-Heusler YPtBi which is a topological semimetal with j=3/2 quasiparticles. The angle-dependent quantum oscillation exhibits striking anisotropy, and the London penetration depth varies as almost temperature-linear, both of which are not easily expected in a compound with cubic symmetry. These anomalous behaviors can be explained within j=3/2 Fermi surface and high-spin superconductivity.