  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.
