Strain-tunable magnetic and electronic properties of a CuCl monolayer

Recently, theoretical search has found that a two-dimensional CuCl₃ monolayer is a ferromagnetic semiconductor. Here, we apply density functional theory to study its geometrical structure, magnetic and electronic properties under the influence of a biaxial strain ε. It is found that the CuCl₃ monolayer exhibits ferromagnetic ordering at the ground state with ε = 0 and its Curie temperature increases monotonously with respect to the biaxial strain, which can be increased to about 100 K at 10% tensile strain. When a compressive strain of about 6.8% is applied, a transition from the ferromagnetic to the antiferromagnetic state occurs. In addition to the transition of the magnetic ground state, the electronic band gaps of spin-up and spin-down electrons undergo direct-indirect and indirect-direct-indirect transitions at the tensile strains, respectively. The tunable magnetic and electronic properties investigated in this work are helpful in understanding the magnetism in the CuCl₃ monolayer, which is useful for the design of spintronic devices based on ferromagnetic semiconductors.