Abstract
The physics of oxide superlattices is considered for pristine (001) multilayers of the band insulators and with alternating and interfaces. A model of charged capacitor plates offers a simple paradigm to understand their dielectric properties and the insulator to metal transition (IMT) at interfaces with increasing layer thicknesses. The model is supported by first-principles results based on density-functional theory. The charge at insulating interfaces is argued and 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.
- Received 11 May 2009
DOI:https://doi.org/10.1103/PhysRevB.80.045425
©2009 American Physical Society