Electric-field control of the exchange interactions

TL;DR

This study investigates how applying an electric field influences exchange interactions in ultrathin Fe films using first-principles calculations, revealing substrate-dependent effects especially at the Fe/Pt interface.

Contribution

It provides a detailed first-principles analysis of electric-field effects on exchange interactions in Fe monolayers, highlighting substrate-specific influences and interface electronic states.

Findings

Electric field significantly alters exchange interactions in Fe monolayers.

Pronounced changes occur in Fe/Pt(111) due to localized interface states.

Substrate choice critically affects the electric-field response of magnetic interactions.

Abstract

The impact of an applied electric field on the exchange coupling parameters has been investigated based on first-principles electronic structure calculations by means of the KKR Green function method. The calculations have been performed for a Fe film, free-standing and deposited on two different substrates, having 1 monolayer (ML) thickness to minimize the effect of screening of the electric field typical for metallic systems. By comparing the results for the free-standing Fe ML with those for Fe on the various substrates, we could analyze the origin of the field-induced change of the exchange interactions. Compared to the free-standing Fe ML, in particular rather pronounced changes have been found for the Fe/Pt(111) system due to the localized electronic states at the Fe/Pt interface, which are strongly affected by the electric field and which play an important role for the Fe-Fe exchange interactions.