Microscopic understanding of the orbital splitting and its tuning at oxide interfaces

¹ Institute of Solid State Physics, Vienna University of Technology - A-1040 Vienna, Austria, EU
² Institut für Theoretische Physik und Astrophysik, Universität Würzburg Am Hubland, D-97074 Würzburg, Germany, EU

Received: 15 June 2012
Accepted: 13 July 2012

Abstract

By means of a Wannier projection within the framework of density functional theory, we are able to identify the modified c-axis hopping and the energy mismatch between the cation bands as the main source of the t_2g splitting around the Γ-point for oxide heterostructures, excluding previously proposed mechanisms such as Jahn-Teller distortions or electric-field asymmetries. Interfacing LaAlO₃, LaVO₃, SrVO₃ and SrNbO₃ with SrTiO₃ we show how to tune this orbital splitting, designing heterostructures with more d_xy electrons at the interface. Such an “orbital engineering” is the key for controlling the physical properties at the interface of oxide heterostructures.