Tuning Néel-vector anisotropy of two-dimensional antiferromagnetic MXene V ₂ CF ₂ by strain and V ₂ CFX (X=OH, Cl, O, H) by Janus engineering

Due to the high-speed data writing, dense storage capacity and strong anti-interference capabilities, the antiferromagnetism of materials has garnered significant research attention. Achieving adjustable Néel-vector anisotropy is crucial for low-energy data writing in antiferromagnetic storage systems. This study explores the control of Néel-vector anisotropy in the antiferromagnetic 2D MXene V 2 CF 2 using density functional theory, focusing on physical strain and chemical modifications. Our results show that the Néel-vector anisotropy in V 2 CF 2 exhibits an in-plane uniaxial character, which can be tuned by both in-plane tensile strain and vertical compression strain. Moreover, Janus engineering, achieved by substituting the F atom on one side of the V 2 CF 2 structure with an O/H atom, can switch the in-plane Néel-vector easy axis to the out-of-plane easy axis. Further analysis of the density of states and orbital-resolved magnetic anisotropy reveals that the redistribution of d orbitals near the Fermi level is responsible for tuning the Néel-vector anisotropy in V 2 CF 2 through strain and Janus-scheme functional group modification.