Qi Zhang, Mithun Ghosh, Yaroslav Zhumagulov, Oldřich Cicvárek, Yuan Chen, Fangchao Long, Yijie Lin, Ali Al Mejamai, Johan Félisaz, Iva Plutnarová, Jianmin Yang, Hue Thi Bich Do, Jan Plutnar, Michel Bosman, Shengqiang Zhou, Goki Eda, Oleg V Yazyev, Zdeněk Sofer, Ahmet Avsar
Dilute magnetic semiconductors (DMSs) provide a platform for electrically controlling spin interactions; however, conventional systems face limited gate tunability and structural disorder. Here, we demonstrate gate-switchable magnetism in air-stable, dilute Fe-doped PtSe2, a two-dimensional (2D) DMS that remains structurally homogeneous down to the atomically thin limit. Bulk crystals exhibit ferromagnetism with a Curie temperature of 320 kelvin, and this coupling persists in metallic devices down to seven layers. As thickness and carrier concentration further decrease, the system transitions to antiferromagnetic order, with a gate-tunable Néel temperature reaching 105 kelvin in five-layer semiconducting devices. Our first-principles calculations reveal a carrier-density-dependent crossover from Ruderman-Kittel-Kasuya-Yosida-mediated ferromagnetism to superexchange-driven antiferromagnetism. These findings demonstrate how induced magnetic order evolves from bulk to the 2D limit, providing a pathway to functional spintronic devices with electrically controlled magnetic states.