Spin-Filtering Multiferroic-Semiconductor Heterojunctions

TL;DR

This study investigates the interface between multiferroic YMnO$_3$ and GaN, revealing spin-dependent band offsets and potential for magnetic tunnel junctions due to polarization-dependent energy barriers.

Contribution

It provides first-principles insights into the spin-dependent electronic structure of YMnO$_3$/GaN heterojunctions, highlighting their potential for spintronic applications.

Findings

Spin-up and spin-down band offsets differ at the interface.

The energy barrier varies with the relative polarization orientation.

Interface induces spin splitting in the valence band.

Abstract

We report on the structural and electronic properties of the interface between the multiferoic oxide YMnO$_3$ and wide band-gap semiconductor GaN studied with the Hubbard-corrected local spin density approximation (LSDA+U) to density-functional theory (DFT). We find that the band offsets at the interface between antiferromagnetically ordered YMnO$_3$ and GaN are different for spin-up and spin-down states. This behavior is due to the spin splitting of the valence band induced by the interface. The energy barrier depends on the relative orientation of the electric polarization with respect to the polarization direction of the GaN substrate suggesting an opportunity to create magnetic tunnel junctions in this materials system.