June 9, 2015
Journal Article

Dominance of interface chemistry over the bulk properties in determining the electronic structure of epitaxial metal/perovskite oxide heterojunctions

Abstract

We show that despite very similar crystallographic properties and work function values in the bulk, epitaxial Fe and Cr metallizations on Nb:SrTiO3(001) generate completely different heterojunction electronic properties. Cr is Ohmic whereas Fe forms a Schottky barrier with a barrier height of 0.50 eV. This contrast arises because of differences in interface chemistry. In contrast to Cr [Chambers, S. A. et al., Adv. Mater. 2013, 25, 4001.], Fe exhibits a +2 oxidation state and occupies Ti sites in the perovskite lattice, resulting in negligible charge transfer to Ti, upward band bending, and Schottky barrier formation. The differences between Cr and Fe are understood by performing first-principles calculations of the energetics of defect formation which corroborate the observed interface chemistry and structure.

Revised: November 16, 2020 | Published: June 9, 2015

Citation

Chambers S.A., Y. Du, M. Gu, T.C. Droubay, S. Hepplestone, and P.V. Sushko. 2015. Dominance of interface chemistry over the bulk properties in determining the electronic structure of epitaxial metal/perovskite oxide heterojunctions. Chemistry of Materials 27, no. 11:4093-4098. PNNL-SA-108999. doi:10.1021/acs.chemmater.5b01118