Dynamical Mean Field Study of Model Double-Exchange Superlattices

TL;DR

This study uses dynamical mean field theory to analyze the electronic and magnetic phases of [001] double-exchange superlattices in perovskite structures, revealing the importance of Coulomb screening length.

Contribution

It introduces a theoretical framework combining dynamical mean field and Hartree approximations to study phase behavior in double-exchange superlattices.

Findings

Identification of phase types and interface classifications.

Highlighting the role of Coulomb screening length.

Insights into charge and spin arrangements in superlattices.

Abstract

A theoretical study of [001] "double exchange" superlattices is presented. The superlattice is defined in terms of an $AB$O$_3$ perovskite crystal. Itinerant electrons hop among the B sites according to a nearest-neighbor tight binding model and are coupled to classical "core spins". The $A$ sites contain ionic charges arranged to form an [001] superlattice which forces a spatial variation of the mobile electron charge on the $B$ sites. The double-exchange interaction is treated by the dynamical mean field approximation, while the long range Coulomb interaction is taken into account by the Hartree approximation. We find the crucial parameter is the Coulomb screening length. Different types of phases are distinguished and the interfaces between them classified.