Effect of the undoped BaSnO$_{3}$ space layer on the high mobility LaInO$_{3}$/Ba$_{1-x}$La$_{x}$SnO$_{3}$ polar interface

We have recently reported on the sheet conductance enhancement at the interface between two band insulators: LaInO$_{3}$ (LIO) and BaSnO$_{3}$ (BSO) [1, 2]. The advantages of the two-dimensional electron gas-like (2DEG) state at the LIO/Ba$_{1-x}$La$_{x}$SnO$_{3}$ (BLSO) polar interface are its stability, the controllability of the local carrier concentration, and the high electron mobility of BLSO [3]. The origin of enhanced conductance at the interface is still under investigation, but the doping level of BSO is a critical parameter for the polar charge contribution. [2] We have investigated a new structure using an undoped BSO space layer at the LIO/BLSO interface. On one hand, this new structure will improve the mobility of the LIO/BLSO structure by reducing La impurity scattering. On the other hand, through this new structure we can answer the issues related with La diffusion at the LIO/BLSO polar interface and trace the origin of the 2DEG-like charge. This new modified structure of the LIO/BSO polar interface looks promising for higher electron mobility devices. [1] U. Kim \textit{et al}., APL Mat. \textbf{3}, 036101 (2015). [2] U. Kim \textit{et al}., preprint. [3] H. J. Kim, U. Kim \textit{et al.}, Appl. Phys. Express \textbf{5}, 061102 (2012).