Quantum oscillations from a two-dimensional electron gas at a Mott/band   insulator interface
  We report on the magnetotransport properties of a prototype Mott insulator/band insulator perovskite heterojunction in magnetic fields up to 31 T and at temperatures between 360 mK and 10 K. Shubnikov-de Haas oscillations in the magnetoresistance are observed. The oscillations are two-dimensional in nature and are interpreted as arising from either a single, spin-split subband or two subbands. In either case, the electron system that gives rise to the oscillations represents only a fraction of the electrons in the space charge layer at the interface. The temperature dependence of the oscillations are used to extract an effective mass of ~ 1 me for the subband(s). The results are discussed in the context of the t2g-states that form the bottom of the conduction band of SrTiO3. 
Pouya Moetakef, Daniel G. Ouellette, James R. Williams, S. James   Allen, Leon Balents, David Goldhaber-Gordon, Susanne Stemmer
cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.str-el