Control of the asymmetric band structure in Mn2Au by a ferromagnetic driver layer

TL;DR

This study demonstrates how a ferromagnetic layer can control the asymmetric band structure in Mn2Au, revealing the underlying electronic and magnetic interactions through advanced spectroscopy techniques.

Contribution

It introduces a method to manipulate and directly measure the asymmetric band structure in Mn2Au using a ferromagnetic driver layer and hard X-ray photoemission spectroscopy.

Findings

Exchange bias aligns the Neel vector in Mn2Au.

Asymmetry in the band structure is measured and linked to the Neel vector orientation.

The band structure asymmetry is confirmed to be antiparallel to the Permalloy magnetization.

Abstract

Hard X-ray angle-resolved photoemission spectroscopy reveals the momentum-resolved band structure in an epitaxial Mn2Au(001) film capped by a 2 nm thick ferromagnetic Permalloy layer. By magnetizing the Permalloy capping layer, the exceptionally strong exchange bias aligns the Neel vector in the Mn2Au(001) film accordingly. Uncompensated interface Mn magnetic moments in Mn2Au were identified as the origin of the exchange bias using X-ray magnetic circular dichroism in combination with photoelectron emission microscopy. Using time-of-flight momentum microscopy, we measure the asymmetry of the band structure in Mn2Au resulting from the homogeneous orientation of the Neel vector. Comparison with theory shows that the Neel vector, determined by the magnetic moment of the top Mn layer, is antiparallel to the Permalloy magnetization. The experimental results demonstrate that hard X-ray photoemission spectroscopy can measure the band structure of epitaxial layers beneath a metallic capping layer and corroborate the asymmetric band structure in Mn2Au that was previously inferred only indirectly.