We study origin of Rashba spin-orbit interaction at SrTiO3 surfaces and LaAlO3/SrTiO3 interfaces by considering the interplay between atomic spin-orbit coupling and inversion asymmetry at the surface or interface. We show that, in a simple tight-binding model involving 3d t2g bands of Ti ions, the induced spin-orbit coupling in the dxz and dyz bands is cubic in momentum whereas the spin-orbit interaction in the dxy band has linear momentum dependence. We also find that the spin-orbit interaction in one-dimensional channels at LaAlO3/SrTiO3 interfaces is linear in momentum for all bands. We discuss implications of our results for transport experiments on SrTiO3 surfaces and LaAlO3/SrTiO3 interfaces. In particular, we analyze the effect of a given spin-orbit interaction term on magnetotransport of LaAlO3/SrTiO3 by calculating weak anti-localization corrections to the conductance and to universal conductance fluctuations.
@article{arxiv.1304.0464,
title = {Origin and Transport Signatures of Spin-Orbit Interactions in One- and Two-Dimensional SrTiO$_3$-Based Heterostructures},
author = {Younghyun Kim and Roman M. Lutchyn and Chetan Nayak},
journal= {arXiv preprint arXiv:1304.0464},
year = {2013}
}