Defect induced magnetism in monolayer semiconducting PtSe2

Intrinsic disorders such as metal vacancies and antisites in 2D TMDCs are generally accompanied by local magnetic moments which could induce long range magnetic ordering if disorder concentration is sufficient. Towards this, we have recently shown that platinum (Pt) vacancy defects located at the surfaces of multilayer metallic PtSe₂ act as magnetic centers [1]. For both fundamental studies and technological applications, it is critical to explore magnetism in ultra-thin PtSe₂ as this material shows a complete switching from a metal to a semiconductor as its thickness is reduced [2]. Here, we will present our magneto-transport measurements together with first-principles calculations which clearly demonstrate that Pt vacancy defect yields an antiferro- (ferro-)magnetic ordering in mono (bi-)layer PtSe₂. We will also demonstrate that these air-stable crystals can be employed as a magnetic substrate to induce novel proximity phenomena into adjacent nonmagnetic layers. Our findings broaden the horizon of 2D magnets to include normally nonmagnetic stable materials by defect engineering.
[1] A. Avsar, A. Ciarrocchi, M. Pizzochero, D. Unuchek, O. V. Yazyev, and A. Kis, Nature Nanotechnol. 14, 674 (2019).
[2] A. Ciarrocchi, A. Avsar, D. Ovchinnikov, and A. Kis, Nature Comm. 9, 919 (2018).