Optical tuning of magnetism with valley polarized excitation

Magnetic 2D materials hold great promises to allow a more active control of magnetism. By interfacing other 2D monolayers with the atomically flat magnet, we can create new functional materials that combines different features and properties. In this talk, I would present my work on the heterostructure of ferromagnetic CrBr₃ and monolayer transition metal dichalcogenide (TMDC) of WSe₂. I would show how the optical excitation within the WSe₂ would also affect the magnetism in CrBr₃. By employing circularly polarized light, valley and spin polarized carriers are created within the TMDC as a result of the valley optical selection rule. Sequential modification in the magnetic response in CrBr₃ indicates that there exists efficient spin transfer from the excited TMDC into the interfaced magnet. Further characterizations including temperature dependence, excitation detuning etc. would also be discussed. The efficient optical tuning of magnetism opens up promising directions to manipulate magnetic domains in an all-optical method.