Correlated electronic states at a ferromagnetic oxide interface

TL;DR

This paper develops a minimal tight-binding model for LaAlO3/SrTiO3 interfaces with oxygen vacancies, revealing how magnetic impurities influence electronic states and transport properties in a disordered ferromagnetic system.

Contribution

It introduces a combined CPA and DMFT approach to model magnetic impurity effects at oxide interfaces, highlighting the disordered Fermi-liquid regime and spin-dependent transport.

Findings

Disordered Fermi-liquid behavior for majority spins.

Low energy scale affecting minority-spin transport.

Magnetic impurities induce spin-dependent electronic states.

Abstract

We propose a minimal tight-binding model for the electronic interface layer of the LaAlO$_3$/SrTiO$_3$ heterostructure with oxygen vacancies. In this model, the effective carriers are subject to oxygen vacancy induced magnetic impurities. Both the effects of random on-site potentials and Zeeman-like exchange interactions between correlated carriers and magnetic impurities are taken into account. By applying the combined coherent potential approximation (CPA) and dynamical mean-field theory (DMFT) for a ferromagnetic state, we uncover a disordered Fermi-liquid regime for the majority-spins and a low energy scale which controls the transport of the minority-spin carriers, both induced by the magnetic impurities.