Inhomogeneous superconductivity in (001), (110), and (111) KTaO3 two-dimensional electronic gases: Effect of electronic confinement on the transition temperature

Experimental observations on KTaO3 superconductivity report widely different critical temperatures with a clear hierarchy among different crystallographic orientations. Accounting for spatial confinement, we connect the inhomogeneous superconducting order parameter with the spatial extent of the two-dimensional electron gas. We reproduce the observed hierarchy within a unified framework, based on a self-consistent tight-binding slab model with local spin-singlet 𝑠-wave pairing. The methods developed here can be readily extended to include more general interaction models, while still consistently including the characteristic spatial structure of the electron gas.