Band alignment, built-in potential, and the absence of conductivity at the LaCrO3/SrTiO3(001) heterojunction

Phys Rev Lett. 2011 Nov 11;107(20):206802. doi: 10.1103/PhysRevLett.107.206802. Epub 2011 Nov 7.

Abstract

Core-level and valence-band x-ray photoemission spectra measured for molecular-beam-epitaxy-grown LaCrO(3)/SrTiO(3)(001) yield band offsets and potential gradients within the LaCrO(3) sufficient to trigger an electronic reconstruction to alleviate the polarity mismatch. Yet, the interface is insulating. Based on first principles calculations, we attribute this unexpected result to interfacial cation mixing combined with charge redistribution within CrO(2) layers, enabled by low-lying d states within LaCrO(3), which suppresses an electronic reconstruction.