Spin, Orbital and Charge Order at the Interface between Correlated Oxides

TL;DR

This paper investigates the complex interplay of spin, orbital, and charge orders at the LaVO$_3$/SrTiO$_3$ interface, revealing a ferromagnetic ground state with orbital and charge orderings that explain the insulating behavior.

Contribution

It presents a theoretical model showing how electron correlations and geometry induce ferromagnetism and charge/orbital orderings at oxide interfaces.

Findings

Ground state is ferromagnetic due to double exchange.

Orbital and charge density waves open gaps on Fermi surfaces.

The model explains the insulating behavior of the p-type interface.

Abstract

The collective behavior of correlated electrons in the VO$_2-$interface layer of LaVO$_3$/SrTiO$_3$ heterostructure is studied within a quarter-filled $t_{2g}$-orbital Hubbard model on a square lattice. We argue that the ground state is ferromagnetic driven by the double exchange mechanism, and is orbitally and charge ordered due to a confined geometry and electron correlations. The orbital and charge density waves open gaps on the entire Fermi surfaces of all orbitals. The theory explains the observed insulating behavior of the $p$-type interface between LaVO$_3$ and SrTiO$_3$.