EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Controlling magnetic properties by tuning carrier concentration is a key feature of diluted ferromagnetic semiconductors, giving possibilities for multifunctional spintronic devices. Here, the evidence of the long-range magnetic order in V-doped WSe2 semiconductors will be presented. The magnetic domains of the long-range ferromagnetic order are observed by magnetic force microscopy at room temperature. More importantly, the magnetic domains can be modulated by a gate bias, which is concrete evidence for the ferromagnetic semiconducting characteristics. The mechanism behind the formation of the long-range order will be also discussed and investigated through scanning tunneling spectroscopy and density functional theory.
In addition, the giant Zeeman shift from the spin-polarized state in WSe2 doped with a small amount of vanadium atoms (~0.15%) by investigating resonant magnetotunneling spectroscopy of a vertical graphite/V-WSe2/graphite heterojunction will be discussed. The p-type character of the doping state is located near the valence band, substantially shifted under an external magnetic field at 7.8 meV/T with a giant g factor of approximately 135, an order of magnitude higher than that of other 2D magnetic semiconductors. The evidence of the spin-polarized band edges of V-doped WSe2 is also confirmed by circular-polarized photoluminescence.