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 31T and at temperatures between 360mK 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 is used to extract an effective mass of similar to 1 m(e) for the subband(s). The results are discussed in the context of the t(2g)-states that form the bottom of the conduction band of SrTiO3. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4758989]