Dichotomous Temperature Response in the Electronic Structure of Epitaxially Grown Altermagnet MnTe

The altermagnet candidate MnTe has recently gained significant interest due to its unconventional magnetic ordering. One of the key features of altermagnetism is the momentum-dependent spin-split band and its temperaturedependent evolution. Yet a fully momentum-resolved experimental investigation, including out-of-plane direction, is still lacking. Here, we systematically investigate the electronic structure of epitaxially grown MnTe by using angle-resolved photoemission spectroscopy (ARPES). Our photon-energy-dependent ARPES data reveal significant out-of-plane dispersions consistent with previous theoretical calculations. More interestingly, we identify two distinct temperature-dependent electronic band structure evolutions at different out-of-plane momentum positions: momentum-dependent energy shifts at the nodal plane and substantial spectral weight suppression at the off-nodal plane. These findings may suggest the importance of considering both the itinerant and localized nature of the magnetic ordering and momentum-dependent interactions. Our work provides crucial insights into the complex correlation between momentum, temperature, and electronic structure in MnTe, contributing to a deeper understanding of altermagnetism.. Authors: Lee, Ji-Eun [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Pohang Univ. of Science and Technology (POSTECH) (Korea, Republic of)] (ORCID:0000000204781030); Zhong, Yong [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES); Stanford Univ., CA (United States)] (ORCID:0000000342422503); Li, Qile [Monash Univ., Melbourne, VIC (Australia)] (ORCID:0000000173741692); Edmonds, Mark T. [Monash Univ., Melbourne, VIC (Australia); Victorian Node of the Australian National Fabrication Facility, Clayton, VIC (Australia)] (ORCID:0000000180545470); Shen, Zhi-Xun [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES); Stanford Univ., CA (United States)]. DOE Contract: AC02-05CH11231; AC02-76SF00515. Subjects: 77 NANOSCIENCE AND NANOTECHNOLOGY; ARPES; MnTe; altermagnet; electronic band structures; molecular beam epitaxy