Large band offset as driving force of 2-dimensional electron confinement: the case of SrTiO$_3$/SrZrO$_3$ interface

Abstract

Using advanced first-principles calculations we predict that the non-polar SrTiO$_3$/SrZrO$_3$ (001) interface, designed as either thin SrZrO$_3$ film deposited on SrTiO$_3$ or short-period (SrTiO$_3$)$_m$/(SrZrO$_3$)$_n$ superlattice, host a 2-dimensionally confined electron gas. Mobile electron charge due to native impurities, field-effect, or modulation doping remains tightly trapped at the interface. Key ingredients for this occurrence are a) the peculiar chemistry of 3d orbitals, b) the large band offset at titanate-zirconate interface.