Intralayer strain tuned interlayer magnetism in bilayer CrSBr

Jun 17, 2024

Nanshu Liu, Cong Wang, Changlin Yan, Changsong Xu, Jun Hu, Yanning Zhang, and Wei Ji

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.