Metallic antiferromagnets are essential for efficient spintronic applications due to their fast switching and high mobility, yet room-temperature metallic antiferromagnets are rare. Here, we investigate YbMn2Ge2, a room temperature antiferromagnet, and establish it as an exfoliable layered metal with altermagnetic surface states. Using multi-orbital Hubbard model calculations, we reveal that its robust metallic AFM ordering is stabilized by electronic correlations and a partially nested Fermi surface. Furthermore, we show that YbMn2Ge2 hosts symmetry-protected topological Dirac crossings, connecting unique even-order spin-polarized surface states with parabolic and inverted Mexican-hat-like dispersion. Our findings position YbMn2Ge2 as a promising platform for exploring the interplay of correlation, topology, and surface altermagnetism of layered antiferromagnets.
@article{arxiv.2503.07206,
title = {Layered Topological Antiferromagnetic Metal at Room Temperature -- YbMn$_2$Ge$_2$},
author = {Nirmalya Jana and Atasi Chakraborty and Anamitra Mukherjee and Amit Agarwal},
journal= {arXiv preprint arXiv:2503.07206},
year = {2025}
}