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arXiv · 2503.07206

Layered Topological Antiferromagnetic Metal at Room Temperature -- YbMn$_2$Ge$_2$

Nirmalya Jana·Atasi Chakraborty·Anamitra Mukherjee·Amit Agarwal
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Abstract

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 YbMn$_2$Ge$_2$, 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 YbMn$_2$Ge$_2$ 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 YbMn$_2$Ge$_2$ as a promising platform for exploring the interplay of correlation, topology, and surface altermagnetism of layered antiferromagnets.

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Nirmalya Jana, Atasi Chakraborty, Anamitra Mukherjee, Amit Agarwal. 2025-03-10. Layered Topological Antiferromagnetic Metal at Room Temperature -- YbMn$_2$Ge$_2$. https://doi.org/10.1103/34g5-q2g6

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