2DEG state at LaInO₃/BaSnO₃ interface

In order to identify the origin of the large conductance enhancement in the polar interface of LaInO₃/BaSnO₃, we studied the variation of the conductance enhancement in LaIn_1-xGa_xO₃/BaSnO₃ interface. We found that the magnitude of the conductance enhancement decreased as Ga ratio increased and eventually completely disappeared in the case of LaGaO₃/BaSnO₃. The conductance of the interface, when present, reached its maximum values when LaIn_1-xGa_xO₃ was about 4 unit cell thick, beyond which the conductance started to decrease slowly. Based on such findings, we developed a model for interface polarization in LIO, in which the polarization exists only in the 4 unit cell thick LIO near the interface. Such a model, when aided by 1D Poisson-Schrödinger equation, produces the n_2D consistent with the experimental results. In addition, by introducing a deep donor density in LIO, we are able to fit the slow relaxation of the interface conductance. Our complete model, comprised of interface polarization in the 4 unit cell thick LIO and the resulting 2DEG state in BSO with 2 nm confinement length, also explains in a consistent way the entire experimental data of the recent doping dependence of the LIO/BLSO interface conductance on both SrTiO₃ and MgO substrates.