Multiband Conduction at the PrAlO₃/SrTiO₃ Interface

We have measured a set of magneto-transport data for the interface between a SrTiO₃ substrate and 15 monolayers of PrAlO₃ synthesized at different oxygen pressures PO₂ during growth. For the interfaces grown at low PO₂, Hall effect data suggest that the transport is dominated by one type of carrier. For these samples, the out-of-plane and in-plane magnetoresistances are positive and negative, respectively (for the measured temperature range of 2 K < T < 100 K). For interfaces grown at high PO₂, at low and high temperatures, T < 5 K and T > 50 K, Hall data could be described by a single channel of electron carriers with a low mobility. At intermediate temperatures 10 K < T < 40 K, the Hall data becomes noticeably nonlinear, with positive out-of-plane and in-plane magnetoresistance. The nonlinear Hall resistance can be described by a two-band model with different electron charge carrier types: one band with low mobility and a high carrier density, and another band with high mobility and a low carrier density.