Superconductivity and Strong Spin-Orbit Coupling in LaBi₂ Thin Films

Novel superconductors containing heavy constituent elements are of great interest for studying the effects of strong spin-orbit coupling on the superconducting ground state, among them extreme resilience to external fields, mixed singlet-triplet pairing, and non-trivial topology in the superconducting order parameter. In this talk we discuss the low-T transport properties of LaBi2 thin-films synthesized via MBE. We observe superconductivity below 500 mK which is previously unreported in bulk synthesis studies. The profound resilience of Tc to film thickness allows us to approach an ultra-thin limit of nearly 2 nm, where a substantial violation of the conventional Pauli-limit reveals strong spin-orbit interactions in the compound's conductive Bi square-nets. Interpretations of various superconductivity models will be discussed with a focus on the temperature-dependence of the parallel critical field. Ongoing and future experiments will also be highlighted which aim to (a) uncover the underlying symmetry of the order parameter and the mechanism for Pauli-limit violation, and (b) utilize the system as a platform for engineering unconventional Cooper pairing in ultra-thin heterostructures.