Electronic structure induced reconstruction and magnetic ordering at the LaAlO$_3|$SrTiO$_3$ interface

TL;DR

This study uses LDA calculations to predict structural distortions and magnetic ordering at the LaAlO3|SrTiO3 interface, providing insights into the electronic and magnetic phenomena observed experimentally.

Contribution

It introduces a theoretical prediction of octahedral rotations and magnetic ordering at the interface, linking structural distortions to magnetic properties.

Findings

GdFeO3-like rotation of TiO6 octahedra at the interface

Charge and spin ordering predicted with LDA+U calculations

Proximity of antiferromagnetic and ferromagnetic states explains experimental magnetism

Abstract

Using local density approximation (LDA) calculations we predict GdFeO$_3$-like rotation of TiO$_6$ octahedra at the $n$-type interface between LaAlO$_3$ and SrTiO$_3$. The narrowing of the Ti $d$ bandwidth which results means that for very modest values of $U$, LDA$+U$ calculations predict charge and spin ordering at the interface. Recent experimental evidence for magnetic interface ordering may be understood in terms of the close proximity of an antiferromagnetic insulating ground state to a ferromagnetic metallic excited state.