Electronic and magnetic properties of the (001) surface of hole-doped manganites

TL;DR

This study investigates how the (001) surface of hole-doped manganites affects their electronic and magnetic properties, revealing surface-induced orbital occupation differences, localization effects, and changes in Mn valency through combined model and ab initio calculations.

Contribution

It provides new insights into surface and interface effects on orbital occupation, localization, and magnetic exchange in doped manganites using advanced computational methods.

Findings

Surface breaks cubic symmetry, altering e_g orbital occupation.

Surface localization of one orbital changes Mn valency from 4 to 3.

Surface/interface localization influences magnetic exchange coupling.

Abstract

The electronic and magnetic properties of ferromagnetic doped manganites are investigated by means of model tight-binding and \textit{ab initio} self-interaction corrected local spin density approximation calculations. It is found that the surface alone by breaking the cubic symmetry induces a difference in the occupation of the two $e_{g}$ orbitals at the surface. With \textit{ab initio} calculations we found surface localisation of one orbital and hence a change in the Mn valency from four in the bulk to three at the sub-surface. Different surface or disordered interface induced localisation of the orbitals are considered too with respect to the nature and the strength of the magnetic exchange coupling between the surface/interface and the bulk-like region.