Electronic reconstruction in correlated electron heterostructures

TL;DR

This paper discusses how electronic phase behavior changes at surfaces and interfaces in correlated-electron systems, emphasizing the importance of electronic reconstruction for understanding and designing novel electronic devices.

Contribution

It provides a theoretical overview of electronic reconstruction in heterostructures, highlighting the universal occurrence of metallic interfaces and altered magnetic orderings in thin correlated-electron layers.

Findings

Interface regions are always metallic, about three-unit-cells wide.

Spin and orbital orderings differ from bulk in heterostructures.

Predictions for photoemission experiments and magnetic phase diagrams are provided.

Abstract

Electronic phase behavior in correlated-electron systems is a fundamental problem of condensed matter physics. We argue here that the change in the phase behavior near the surface and interface, i.e., {\em electronic reconstruction}, is the fundamental issue of the correlated-electron surface or interface science. Beyond its importance to basic science, understanding of this behavior is crucial for potential devices exploiting the novel properties of the correlated systems. % We present a general overview of the field, and then illustrate the general concepts by theoretical studies of the model heterostructures comprised of a Mott-insulator and a band-insulator, which show that spin (and orbital) orderings in thin heterostructures are generically different from the bulk and that the interface region, about three-unit-cell wide, is always metallic, demonstrating that {\em electronic reconstruction} generally occurs. % Predictions for photoemission experiments are made to show how the electronic properties change as a function of position, and the magnetic phase diagram is determined as a function of temperature, number of layers, and interaction strength. Future directions for research are also discussed.