Absence of giant spin splitting in the two dimensional electron liquid at the surface of SrTiO3 001

We reinvestigate the putative giant spin splitting at the surface of SrTiO3 reported by Santander Syro et al. [Nat. Mater. 13, 1085 2014 ]. Our spin and angle resolved photoemission experiments on fractured 001 oriented surfaces supporting a two dimensional electron liquid with high carrier density show no detectable spin polarization in the photocurrent. We demonstrate that this result excludes a giant spin splitting while it is consistent with the unconventional Rashba like splitting seen in band structure calculations that reproduce the experimentally observed ladder of quantum confined subband