Temperature-driven dichotomous band responses in epitaxially-grown altermagnet MnTe

MnTe, one of the altermagnet candidates, has attracted attention for its unconventional magnetic ordering. A key aspect of altermagnetism is the momentum-dependent spin-split bands and their temperature evolution, but a fully momentum-resolved study, including out-of-plane dispersion, remains lacking. In this talk, we present the momentum-dependent electronic structure and temperature evolution of MnTe, studied by molecular beam epitaxy (MBE) and angle-resolved photoemission spectroscopy (ARPES). Our photon-energy-dependent ARPES data reveal strong out-of-plane dispersions that align with theoretical predictions. Notably, we identify two distinct temperature-dependent band evolutions: momentum-dependent energy shifts at nodal planes and substantial spectral weight suppression near the Fermi level at off-nodal planes. These findings suggest a complex interplay between itinerant and localized magnetic moments, contributing to the unique altermagnetic behavior in MnTe. Our study provides critical insights into the microscopic origins of altermagnetic properties and its correlation with temperature and momentum, shedding light on the broader understanding of altermagnetism.