Asymmetric interface profiles in LaVO3∕SrTiO3 heterostructures grown by pulsed laser deposition

Abstract

Surface segregation effects play an important role in the growth of traditional III-V semiconductor heterointerfaces. Here we show that segregation processes can also set an upper limit to the obtainable interface sharpness in perovskite oxide heterostructures. In particular, the structure of LaVO3∕SrTiO3 superlattices was studied on the atomic scale by electron microscopy and spectroscopy. The vanadate layers exhibit a growth asymmetry, with diffuse lower and atomically abrupt upper interfaces, caused by preferential Sr surface segregation. Switching the SrTiO3 termination layer does not change the interface abruptness, which excludes the interfacial polar discontinuity as the driving force for the observed growth asymmetry.