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arXiv · 2610.09664

Vanishing Altermagnetism and Emergent Ferromagnetism at the Two-Dimensional Limit of CrSb

Yunlong Liu·Zixuan Wu·Qinxi Liu·Yupeng Zhi·Mingqiang Ren·Xue Jiang·Canli Song·Ding Zhang·Xucun Ma·Huimin Zhang·Jijun Zhao
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Abstract

Altermagnets offer a promising route to spintronic devices by combining spin-split electronic states with zero net magnetization, but how reduced dimensionality reshapes their magnetic order remains poorly understood. Here, we grow bilayer-thickness CrSb (0001) films directly on SrTiO3(001) substrates by molecular beam epitaxy and uncover an unexpected thickness-dependent magnetic transition. The one-bilayer films exhibit room-temperature ferromagnetism with strong perpendicular magnetic anisotropy, whereas ferromagnetism vanishes in two-bilayer films, contrasting sharply with the altermagnetic ground state of bulk CrSb. Density functional theory calculations reveal that the exposed Cr surface induces orbital rearrangement that strengthens intralayer ferromagnetic exchange while suppressing competing interlayer antiferromagnetic coupling, driving the dimensional crossover from altermagnetism to ferromagnetism. These findings establish dimensionality and surface termination as powerful controls of magnetic order and provide a platform for engineering ultrathin magnetic states for spintronic applications.

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Yunlong Liu, Zixuan Wu, Qinxi Liu, Yupeng Zhi, Mingqiang Ren, Xue Jiang, Canli Song, Ding Zhang, Xucun Ma, Huimin Zhang, Jijun Zhao. 2026-10-07. Vanishing Altermagnetism and Emergent Ferromagnetism at the Two-Dimensional Limit of CrSb. https://doi.org/10.1016/j.newton.2026.100700

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