EXPLORING TRANSITION METAL- AND MAGNETIC MOLECULE-2D VSe2 INTERFACES

Abstract

The common theme of this thesis is about the two-dimensional (2D) vanadium diselenide (VSe2). Cobalt/VSe2 (Co/VSe2), cobalt phthalocyanine molecules/VSe2 (CoPc/VSe2) and molybdenum trioxide and potassium/VSe2 (MoO3/VSe2 and K/VSe2) interfaces as well as the VxMo1−xSe2 alloys are explored. A magnetic transition from disorder to long-range spin order in monolayer VSe2 has been revealed at the Co/VSe2 interface. At the VSe2 edges only, MoO3 reacts with VSe2 to form MoO2 and VO2. MoO3 and K have no obvious charge transfer doping effect on monolayer VSe2. CoPc exhibits two distinctive molecular contrasts on VSe2 with a distinct difference in the electronic state of the central Co atom. 2D VxMo1−xSe2 alloys exhibit a critical value of x = ~0.44, below which phase separation occurs, and above which a homogeneous metallic phase is favored. This work provides a comprehensive understanding of the electronic structure and magnetism of VSe2, useful for future device design.