Oxide superlattices with alternating p and n interfaces

Authors :: Bristowe, N. C.
Artacho, Emilio
Littlewood, P. B.
Publication Year :: 2009
Publisher :: arXiv, 2009.
Abstract: The physics of oxide superlattices is considered for pristine (001) multilayers of the band insulators LaAlO3 and SrTiO3 with alternating p and n interfaces. First principles results and a model of capacitor plates offer a simple paradigm to understand their dielectric properties and the insulator to metal transition (IMT) at interfaces with increasing layer thickness. The charge at insulating interfaces is found to be as predicted from the formal ionic charges, not populations. Different relative layer thicknesses produce a spontaneous polarization of the system, and allow manipulation of the interfacial electron gas. Large piezoresistance effects can be obtained from the sensitivity of the IMT to lateral strain. Carrier densities are found to be ideal for exciton condensation.<br />Comment: 5 pages, 4 pdf figures, 1 added figure and additional references and discussions