Charge transfer in heterostructures of strongly correlated materials

TL;DR

This paper reviews recent theoretical work on charge transfer in oxide multilayers, demonstrating how multilayer engineering can induce metallic and ferromagnetic states in strongly correlated materials, avoiding disorder from chemical doping.

Contribution

It introduces new theoretical results showing how multilayer structures can generate metallic and ferromagnetic states through charge transfer, using Hubbard and Double Exchange models.

Findings

Mixing insulators in multilayers can produce metallic states.

Charge transfer can induce ferromagnetism in multilayer oxides.

Multilayer engineering offers a disorder-free way to explore phase diagrams.

Abstract

In this manuscript, recent theoretical investigations by the authors in the area of oxide multilayers are briefly reviewed. The calculations were carried out using model Hamiltonians and a variety of non-perturbative techniques. Moreover, new results are also included here. They correspond to the generation of a metallic state by mixing insulators in a multilayer geometry, using the Hubbard and Double Exchange models. For the latter, the resulting metallic state is also ferromagnetic. This illustrates how electron or hole doping via transfer of charge in multilayers can lead to the study of phase diagrams of transition metal oxides in the clean limit. Currently, these phase diagrams are much affected by the disordering standard chemical doping procedure, which introduces quenched disorder in the material.