Easy-axis rotation in ferromagnetic monolayer CrN induced by fluorine and chlorine functionalization

Abstract

The schematic energy diagram with crystal-field splitting of the d states before and after functionalization of CrN is reported.

Robust ferromagnetism in two-dimensional GeC/CrN heterobilayers

“…In the absence of the applied strain, the values of magnetic exchange for AA and AB structures are 11.95 meV and 11.99 meV, respectively, which are quite close to the pristine monolayer CrN, i.e., 10.73 meV. 49 However, the value of J is decreasing under the tensile strain while it is increased under compressive strain as shown in Fig. 6(a).…”

“…, 10.73 meV. 49 However, the value of J is decreasing under the tensile strain while it is increased under compressive strain as shown in Fig. 6(a).…”

“…The magnetic anisotropy energy depends on the strength of spin–orbit coupling and the size of the orbital magnetic moment. 16,18,49 It is seen that the energy required to orient the hard axis to the easy axis decreases for the compressive values of strain, while it increases for the tensile strain values. The MAE is crucially important for the formation of finite temperature long range magnetic order in a two-dimensional system.…”

“…The Curie temperature ( T c ), the critical temperature at which the ferromagnetic order transitions to the paramagnetic order, can be calculated within the random phase approximation (eqn (1)). For the out-of-plane (easy axis) aligned spins, the spin wave gap is defined by Δ = S (12 δ + 2 A ) in the framework of the Holstein–Primakoff transformation 34,49 (see the Appendix). In the absence of strain, the Curie temperature for the AA and AB stacks of the GeC/CrN heterostructure is calculated as 950 K and 930 K, respectively.…”

“…33 Moreover, the gas sensing mechanism was recently investigated through the easy axis rotation of monolayer CrN upon single-side adsorption of F and Cl atoms. 49 As a matter of fact, the heterobilayer formation of magnetic and non-magnetic layers by vdW coupling modifies the electronic and magnetic properties of the magnetic layer. 50–55 The effect of biaxial tensile and compressive strain on the electronic structure, magnetic ground state, magnetocrystalline anisotropy, Curie temperature, and valley splitting of the WSe 2 /CrSnSe 3 hetero-structure is examined in ref.…”