title: Electronic and magnetic properties of perfect, vacancy-doped, and nonmetal adsorbed MoSe2, MoTe2 and WS2 monolayers.
abstract: Very recently, two-dimensional nanosheets of MoSe(2), MoTe(2) and WS(2) were successfully synthesized experimentally [Science, 2011, 331, 568]. In the present work, the electronic and magnetic properties of perfect, vacancy-doped, and nonmetal element (H, B, C, N, O, and F) adsorbed MoSe(2), MoTe(2) and WS(2) monolayers are systematically investigated by means of first-principles calculations to give a detailed understanding of these materials. It is found that: (1) MoSe(2), MoTe(2) and WS(2) exhibit surprising confinement-induced indirect-direct-gap crossover; (2) among all the neutral native vacancies of MoSe(2), MoTe(2) and WS(2) monolayers, only the Mo vacancy in MoSe(2) can induce spin-polarization and long-range antiferromagnetic coupling; (3) adsorption of nonmetal elements on the surface of MoSe(2), MoTe(2) and WS(2) nanosheets can induce a local magnetic moment; H-absorbed WS(2), MoSe(2), and MoTe(2) monolayers and F-adsorbed WS(2) and MoSe(2) monolayers show long-range antiferromagnetic coupling between local moments even when their distance is as long as ∼12 Å. These findings are a useful addition to the experimental studies of these new synthesized two-dimensional nanosheets, and suggest a new route to facilitate the design of spintronic devices for complementing graphene. Further experimental studies are expected to confirm the attractive predictions.
authors.affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People's Republic of China.
authors.forename: Yandong
authors.initials: Y
authors.lastname: Ma
authors.forename: Ying
authors.initials: Y
authors.lastname: Dai
authors.forename: Meng
authors.initials: M
authors.lastname: Guo
authors.forename: Chengwang
authors.initials: C
authors.lastname: Niu
authors.forename: Jibao
authors.initials: J
authors.lastname: Lu
authors.forename: Baibiao
authors.initials: B
authors.lastname: Huang