Promoting perpendicular magnetic anisotropy and Curie temperature in CrGeTe/PtTeheterostructures

The weak magnetic anisotropy and low Curie temperature of two-dimensional Cr2Ge2Te6 greatly restrict its application in spintronics. In this work, a simple but effective strategy has been proposed to promote the perpendicular magnetic anisotropy and Curie temperature of monolayer Cr2Ge2Te6, via stacking into van der Waals heterostructure with monolayer PtTe2. Based on first-principles calculations, the Cr2Ge2Te6/PtTe2 heterostructures are demonstrated to significantly enhance the magnetic anisotropy, which is improved from -0.06 meV Cr-1 for the monolayer into 0.24 meV Cr-1 for the heterostructure. By analyzing the orbit-resolved magnetic anisotropy and the projected density of states, it is revealed that the enhancement of magnetic anisotropy energy is closely related to interface Te atoms of monolayer Cr2Ge2Te6. The Curie temperature of the heterostructure is estimated to be 90 K by Monte Carlo simulation, increased by 300% compared with the value of 30 K for monolayer Cr2Ge2Te6. These results suggest the magnetic performance of Cr2Ge2Te6 can be significantly improved by van der Waals engineering. Compared with other methods, such as doping atoms or applying strain, this stacking-strategy is more convenient and controllable. Although there are still important challenges toward the room-temperature ferromagnetism of two-dimensional Cr2Ge2Te6 and other semiconductors, our work has proved a new approach to solve this problem and is of reference value for the design of novel magnetic heterostructures.