Strain-Controlled Magnetocrystalline Anisotropy in Atomically Thin Ir-Stacked 1T-CrTe2

Two-dimensional (2D) ferromagnetic materials with tunable magnetocrystalline anisotropy (MCA) hold great promise for the realization of magnetic tunnel junctions combining enhanced information stability and high energy efficiency. Here, using first-principles calculations, we propose the utilization of an atomically thin Ir capping layer to optimize the electronic structure and magnetic properties of a 1T-CrTe2 monolayer. The influences of the magnetized Ir capping monolayer and various strain effects on the MCA of layered 1T-CrTe2 are investigated. We demonstrate that the stacking configurations and the type of strain play a key role in determining their MCA energy. Notably, the MCA of an Ir-capped structure increases significantly from −1.773 to −4.746 meV/u.c. when the applied uniaxial tensile strain on the a-axis changes from 0 to 2%. The underlying atomic mechanism primarily originates from the strain-induced change of 5d orbital states derived from Ir atoms, which in turn leads to a corresponding competitive variation of the spin–orbit coupling energy between the spin-parallel and spin-flip channels. These results not only reveal a vital scheme for interfacial engineering to control 2D ferromagnets but also provide alternative candidates for the design of ultralow-energy memory devices.