Nanshu Liu, Cong Wang, Changlin Yan, Changsong Xu, Jun Hu, Yanning Zhang, and Wei Ji
Abstract:
Interlayer magnetism was tuned by many interlayer means, e.g., stacking, distance, and external fields in two-dimensional (2D) magnets. As an exception, the interlayer magnetism of CrSBr few layers was, however, experimentally changed by applied intralayer strains [Nat. Nanotechnol. 17, 256 (2022)], the mechanism of which is yet to be unveiled. Here, we uncovered its mechanism by investigating in-plane strained bilayer CrSBr using density functional theory calculations. Under in-plane tensile strain, wavefunction overlaps are strengthened for Br p electrons within each CrSBr layer, which delocalizes intralayer electrons and, as a consequence, promotes interlayer electron hopping. A negative interlayer Poisson’s ratio also enlarges interlayer spacing for bilayer CrSBr, which reduces the interlayer Pauli repulsion. This joint effect, further verified by examining interlayer sliding and interfacial element substitution, leads to an interlayer antiferromagnetic to ferromagnetic transition, consistent with the previous experimental observation. This mechanism enables a route to tune interlayer magnetism by modifying intralayer electron localization in 2D magnets.
Chen Ye, Cong Wang, Qiong Wu, Sheng Liu, Jiayuan Zhou, Guopeng Wang, Aljoscha Söll, Zdenek Sofer, Ming Yue, Xue Liu, Mingliang Tian, Qihua Xiong, Wei Ji & Xiao Renshaw Wang
Abstract
Magnetic van der Waals (vdW) materials possess versatile spin configurations stabilized in reduced dimensions. One magnetic order is the interlayer antiferromagnetism in A-type vdW antiferromagnet, which may be effectively modified by the magnetic field, stacking order, and thickness scaling. However, atomically revealing the interlayer spin orientation in the vdW antiferromagnet is highly challenging, because most of the material candidates exhibit an insulating ground state or instability in ambient conditions. Here, we report the layer-dependent interlayer antiferromagnetic spin reorientation in air-stable semiconductor CrSBr using magnetotransport characterization and first-principles calculations. We reveal an odd–even layer effect of interlayer spin reorientation, which originates from the competitions among interlayer exchange, magnetic anisotropy energy, and extra Zeeman energy of uncompensated magnetization. Furthermore, we quantitatively constructed the layer-dependent magnetic phase diagram with the help of a linear-chain model. Our work uncovers the layer-dependent interlayer antiferromagnetic spin reorientation engineered by magnetic field in the air-stable semiconductor. (DOI: 10.1021/acsnano.2c01151)
Intrinsic antiferromagnetism in van der Waals (vdW) monolayer (ML) crystals enriches our understanding of two-dimensional (2D) magnetic orders and presents several advantages over ferromagnetism in spintronic applications. However, studies of 2D intrinsic antiferromagnetism are sparse, owing to the lack of net magnetisation. Here, by combining spin-polarised scanning tunnelling microscopy and first-principles calculations, we investigate the magnetism of vdW ML CrTe2, which has been successfully grown through molecular-beam epitaxy. We observe a stable antiferromagnetic (AFM) order at the atomic scale in the ML crystal, whose bulk is ferromagnetic, and correlate its imaged zigzag spin texture with the atomic lattice structure. The AFM order exhibits an intriguing noncollinear spin reorientation under magnetic fields, consistent with its calculated moderate magnetic anisotropy. The findings of this study demonstrate the intricacy of 2D vdW magnetic materials and pave the way for their in-depth analysis.
