Influence of the Néel vector on the bulk electronic structure of MnTe measured from the $(1 \bar1 00)$ surface

Abstract

Altermagnetism gives rise to momentum-dependent spin splitting without net magnetization. Here, we use angle-resolved photoemission spectroscopy (ARPES) to investigate bulk $α$-MnTe single crystals cleaved along the $(1\bar{1}00)$ plane - an orientation that preserves the compensated magnetic symmetry at the surface and substantially reduces surface effects and $k_z$ broadening. We resolve the three-dimensional bulk band structure with markedly enhanced spectral clarity. The $d$-wave band splitting, driven by the altermagnetic order and spin-orbit coupling in the $\mathbfΓ-\mathbf{K}-\mathbf{M}$ nodal plane, shows a perfect match to theoretical predictions. We further establish that the valence-band maximum occurs near the $\mathbf{A}$ point, identifying the corresponding hole pockets as the states governing the transport properties. Spatially resolved measurements reveal systematic variations of the band dispersion along $\mathbfΓ-\mathbf{K}$ and $\mathbf{A}-\mathbf{L}$, associated with different pinning of the Néel vector at the surface. Our results establish a surface-sensitive route to resolving the bulk altermagnetic electronic structure of MnTe and provide direct spectroscopic evidence for Néel-vector-dependent band splitting.