"Intrinsic spin-orbit coupling in superconducting δ-doped SrTiO3 heterostructures"

M. Kim: Y. Kozuka, C. Bell, Y. Hikita and H. Y. Hwang; Physical Review B, 08/15/12.

Additional Authors: Y. Kozuka, C. Bell, Y. Hikita and H. Y. Hwang

Abstract:

We report the violation of the Pauli limit due to intrinsic spin-orbit coupling in SrTiO3 heterostructures. Via selective doping down to a few nanometers, a two-dimensional superconductor is formed, geometrically suppressing orbital pair breaking. The spin-orbit scattering is exposed by the robust in-plane superconducting upper critical field, exceeding the Pauli limit by a factor of 4. Moreover, transport scattering times several orders of magnitude higher than for conventional thin-film superconductors enable this system to enter a different regime of cleanliness, where intrinsic band spin-orbit coupling effects arise in these symmetrically doped samples.