Tunable electronic properties and enhanced ferromagnetism in Cr2Ge2Te6 monolayer 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 (TC) of CGT monolayer is only 22K, which greatly hampers the development of the applications based on the CGT materials. Herein, the electronic and magnetic properties of Cr2Ge2Te6 monolayer under the applied strain was explored by density functional theory calculation. 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, it is found that the strain can increase the Curie temperature and magnetic moment, so that largely enhance the ferromagnetism of CGT monolayer. Notably, the obvious enhancement of TC by 191% is achieved at 10% strain. The 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.