Mechanically Robust 2D Magnetic Semiconductor: Anisotropic Elasticity and Fatigue Resistance in CrSBr.

Wang, Yafei; Wang, Guorui; Wu, Xiqi; Li, Jiahao; Li, Houbo; Chen, Xinan; Zhang, Zhao; Zhao, Yuxiang et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Two-dimensional (2D) materials with intrinsic anisotropy offer unique opportunities for direction-dependent functionality, yet their mechanical anisotropy and long-term reliability remain largely unexplored. Here, we systematically investigate the layered magnetic semiconductor CrSBr, revealing strong in-plane elastic anisotropy (<i>E</i><sub><i>a</i></sub>/<i>E</i><sub>b</sub> = 1.43) from angle-resolved atomic force microscopy (AFM) nanoindentation and an out-of-plane modulus of ∼54 GPa from contact resonance AFM, indicative of robust interlayer coupling. Dynamic AFM loading demonstrates pronounced anisotropic fatigue, with superior endurance along the <i>b</i>-axis attributed to enhanced interlayer energy dissipation, consistent with friction measurements and first-principles calculations of interlayer sliding energy. Remarkably, despite its lower fracture strength, CrSBr exhibits fatigue lifetimes comparable to graphene and CVD-grown MoS<sub>2</sub> under normalized stress. These results establish CrSBr as a mechanically robust 2D magnetic semiconductor, where anisotropic bonding and interlayer coupling combined govern cyclic damage resistance.