Band Alignment, Built-In Potential, and the Absence of Conductivity at the ${\mathrm{LaCrO}}_{3}/{\mathrm{SrTiO}}_{3}(001)$ Heterojunction

Band Alignment, Built-In Potential, and the Absence of Conductivity at the ${LaCrO}_{3} / {SrTiO}_{3} (001)$ Heterojunction

S. A. Chambers, L. Qiao, T. C. Droubay, T. C. Kaspar, B. W. Arey, and P. V. Sushko

Phys. Rev. Lett. 107, 206802 – Published 7 November 2011

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.

Received 8 June 2011

DOI:https://doi.org/10.1103/PhysRevLett.107.206802

Authors & Affiliations

S. A. Chambers^1,*, L. Qiao¹, T. C. Droubay¹, T. C. Kaspar¹, B. W. Arey¹, and P. V. Sushko²

¹Pacific Northwest National Laboratory, Richland Washington 99352, USA
²Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, Gower Street, London, WC1E 6BT, United Kingdom