Effective magnetic modulation of monolayer 1T-CrSe2 under small strain: Magnetic ground state and magnetic anisotropy

Strain engineering offers an effective approach to modulating the magnetic properties of two-dimensional materials. In this paper, we investigate the behaviors of the magnetic ground state and magnetic anisotropy in monolayer 1T-CrSe2 under biaxial strain by considering the Kitaev interaction. At zero strain, it exhibits a zigzag antiferromagnetic ground state with a magnetic easy axis being 25° off the out-of-plane direction. This special orientation of the easy axis arises from the competition between the Kitaev interaction and single-ion anisotropy, where K = 0.095 meV, approximately twice the value of Ak. We find that a small tensile strain of 0.3% can induce a magnetic phase transition in 1T-CrSe2 from zigzag to ferromagnetism, primarily driven by the enhanced Heisenberg nearest-neighbor interaction. During the transition, the easy axis shifts abruptly to in plane. Under compressive strain, the easy axis in zigzag ground state gradually tilts toward 85° off the perpendicular axis as strain reaches −1.2%, primarily arising from the strain sensitivity of single-ion anisotropy, where Ak undergoes sign reversal with its magnitude enhanced about twofold. Although the Kitaev interaction remains nearly constant under strain, the presence of it enables this continuous rotation of the easy axis in zigzag. Our study provides a theoretical foundation for strain-engineering magnetic anisotropy in two-dimensional Kitaev materials, with potential applications in spintronic devices such as magnetic sensors and memory elements.