Abstract
Two-dimensional van der Waals (vdW) crystal Fe3GeTe2 exhibits robust 2D ferromagnetism. Fe3GeTe2 nanoflakes have strong perpendicular magnetic anisotropy and a Curie temperature near 200K. The magnetic properties of Fe3GeTe2 highlight its potential for engineering spintronic vdW heterostructures. Monolayer TMDs with a broken inversion symmetry have two inequivalent valleys, and valley polarization can be controlled through the helicity of light. A new approach to valleytronics control is breaking the valley degeneracy by a magnetic field, related to Zeeman effect. The integration of monolayer TMDs with 2D ferromagnetism crystal have large space for research. Ultrathin CrI3-WSe2 heterostructure have been studied, which exhibited excellent control of spin and valley pseudospin in single-layer WSe2. However, CrI3 crystal is unstable in nature and has a lower Curie temperature than Fe3GeTe2, which determine that Fe3GeTe2 is more suitable than CrI3 in the semiconductor industry. In this work, we fabricate Fe3GeTe2-WSe2 heterostructure device by using a polycarbonate-based transfer technique. We hope to achieve the control of spin and valley pseudospin in heterostructure device through a magnetic field and detect the valley pseudospin of monolayer WSe2 by using Polarization-sensitive photoluminescence.
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