Tuning of electronic and magnetic properties in 2D van der Waals hybrid ferromagnet (Fe3GeTe2/Co3GeTe2)

Recent discovery of intrinsic ferromagnetism in Fe3GeTe2 monolayer not only extended the family of 2D magnetic materials, but also stimulated further interest in the possibility to tune their magnetic properties without changing the structural properties or introducing defects. We have studied the role of van-der-Waals (vdW) interaction in such layered materials. It is seen that the incorporation of vdW interaction within density functional theory approach gives more accurate electronic and magnetic properties in 2D vdW ferromagnet. In search of new vdW ferromagnet, we have studied Co3GeTe2 and hybrid layered structure of Fe3GeTe2/Co3GeTe2. Significant changes in magnetic and electronic properties are observed on Co insertion in Fe3GeTe2. Spin polarization of 53% is calculated for Fe3GeTe2, while for Co3GeTe2 and hybrid structure negative spin polarization is obtained. We have observed the reversal of spin polarization due to Co and the amplitude of spin polarization also depends on Co concentration in the layered Fe3GeTe2. Therefore, the intrinsic magnetic properties of 2D vdW ferromagnet can be tuned by making hybrid structure which is very useful in designing new 2D intrinsic magnetic material.