Intrinsic spin-orbit coupling in superconducting {\delta}-doped SrTiO3   heterostructures
  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. Transport scattering times several orders of magnitude higher than for conventional thin film superconductors enables a new regime to be entered, where spin-orbit coupling effects arise non-perturbatively. 
M. Kim, Y. Kozuka, C. Bell, Y. Hikita, and H. Y. Hwang
cond-mat.supr-con cond-mat.str-el