Tunable electronic properties and enhanced ferromagnetism in Cr₂Ge₂Te₆monolayer by strain engineering

Recently, as a new representative of Heisenberg's two-dimensional (2D) ferromagnetic materials, 2D Cr₂Ge₂Te₆(CGT), has attracted much attention due to its intrinsic ferromagnetism. Unfortunately, the Curie temperature (T) of CGT monolayer is only 22 K, which greatly hampers the development of the applications based on the CGT materials. Herein, by means of density functional theory computations, we explored the electronic and magnetic properties of CGT monolayer under the applied strain. It is demonstrated that the band gap of CGT monolayer can be remarkably modulated by applying the tensile strain, which first increases and then decreases with the increase of tensile strain. In addition, the strain can increase the Curie temperature and magnetic moment, and thus largely enhance the ferromagnetism of CGT monolayer. Notably, the obvious enhancement ofTby 191% can be achieved at 10% strain. These results demonstrate that strain engineering can not only tune the electronic properties, but also provide a promising avenue to improve the ferromagnetism of CGT monolayer. The remarkable electronic and magnetic response to biaxial strain can also facilitate the development of CGT-based spin devices.