Structural characterization of LaInO$_{\mathrm{3}}$/BaSnO$_{\mathrm{3}}$ interface via synchrotron scattering

The alkaline earth stannate BaSnO$_{\mathrm{3}}$ has one of the highest measured room-temperature mobilities of the conducting perovskite oxides. FETs based on BaSnO$_{\mathrm{3}}$ display a large on/off ratio, I$_{\mathrm{on}}/$I$_{\mathrm{off}}=$10$^{\mathrm{7}}$, and high field effect mobility, $\mu =$90 cm$^{\mathrm{2}}$/Vs. [1] It has been suggested that in these polar devices, which use a LaInO$_{\mathrm{3}}$ dielectric, the polar discontinuity between the polar LaInO$_{\mathrm{3\thinspace }}$dielectric and the nonpolar Ba$_{\mathrm{0.93}}$La$_{\mathrm{0.07}}$SnO$_{\mathrm{3\thinspace }}$channel leads to an electronic reconstruction. LaInO$_{\mathrm{3\thinspace }}$remotely dopes Ba$_{\mathrm{0.93}}$La$_{\mathrm{0.07}}$SnO$_{\mathrm{3\thinspace }}$with electrons, creating the high observed mobility. Using synchrotron radiation, we measure crystal truncation rods (CTRs) of thin film LIO/BSO/STO grown by pulsed-laser deposition. Fitting these CTRs, we determine a layer-resolved atomic structure for the LIO/BSO interface. We observe octahedral rotations and polarization in the LIO layer for films as thin as 6 unit-cells, similar to the rotations observed in bulk LIO. We discuss how these rotations may be coupled to the polarization near the interface. [1] Kim et al. APL Mater. 3, 036101 (2015)