The response of oxide thin films to polar discontinuities at interfaces and surfaces has generated an enormous activity due to the variety of interesting effects it gives rise to. A case in point is the discovery of the electron gas at the interface between LaAlO3 and SrTiO3, which has since been shown to be quasi-two-dimensional, switchable, magnetic and/or superconducting. Despite these findings, the origin of the two-dimensional electron gas is highly debated and several possible mechanisms remain. Here we review the main proposed mechanisms and attempt to model expected effects in a quantitative way with the ambition of better constraining what effects can/cannot explain the observed phenomenology. We do it in the framework of a phenomenological model for understanding electronic and/or redox screening of the chemical charge in oxide heterostructures. We also discuss the effect of intermixing, both conserving and non-conserving the total stoichiometry.
@article{arxiv.1310.8427,
title = {Origin of two-dimensional electron gases at oxide interfaces: insights from theory},
author = {N C Bristowe and Philippe Ghosez and P B Littlewood and Emilio Artacho},
journal= {arXiv preprint arXiv:1310.8427},
year = {2014}
}