Link between the Superconducting Dome and Spin-Orbit Interaction in the (111) LaAlO3/SrTi O3 Interface

We measure the gate voltage (Vg) dependence of the superconducting properties and the spin-orbit interaction in the (111)-oriented LaAlO3/SrTiO3 interface. Superconductivity is observed in a dome-shaped region in the carrier density-temperature phase diagram with the maxima of superconducting transition temperature Tc and the upper critical fields lying at the same Vg. The spin-orbit interaction determined from the superconducting parameters and confirmed by weak-antilocalization measurements follows the same gate voltage dependence as Tc. The correlation between the superconductivity and spin-orbit interaction as well as the enhancement of the parallel upper critical field, well beyond the Chandrasekhar-Clogston limit, suggest that superconductivity and the spin-orbit interaction are linked in a nontrivial fashion. We propose possible scenarios to explain this unconventional behavior.