Two-Dimensional Magnetic Semiconductors Based on Transition-Metal Dichalcogenides V $X_2$ ($X$ = S, Se, Te) and Similar Layered Compounds VI$_{{2}}$ and Co(OH)$_{{2}}

• Published in: IEEE magnetics letters Vol. 8; pp. 1 - 5
• Main Authors: Fuh, Huei-Ru, Chang, Kai-Wei, Hung, Sheng-Hsiung, Jeng, Horng-Tay
• Format: Journal Article
• Language: English
• Published: Piscataway The Institute of Electrical and Electronics Engineers, Inc. (IEEE) 2017
• Subjects: Energy gap; First principles; Spintronics; Valence
• ISSN: 1949-307X; 1949-3088
• DOI: 10.1109/LMAG.2016.2621720

We present a new type of two-dimensional (2D) magnetic semiconductor based on transition-metal dichalcogenides [Formula Omitted], Se, Te, I, OH) via first-principles calculations. The obtained band gaps of monolayer (ML) VS[Formula Omitted], VSe[Formula Omitted], and VTe[Formula Omitted] in the H-phase given from the generalized gradient approximation (GGA) are respectively 0.05, 0.22, and 0.20 eV, all with integer magnetic moments of 1.0 [Formula Omitted], while ML VI[Formula Omitted] and Co(OH)[Formula Omitted] in the T-phase exhibit energy gaps of 0.96 and 0.08 eV, respectively, with integer magnetic moments of 3.0 [Formula Omitted]. The GGA plus on-site Coulomb interaction U [Formula Omitted] scheme, which takes the electron-electron correlations in 3d orbitals into account, enhances the exchange splittings, and raises the energy gap of these MLs up to 0.4 to 3 eV. They agree very well with our calculated gaps based on the hybridized functional Heyd–Scuseri–Ernzerhof (HSE) of 0.6 to 3 eV. The wide range of energy gaps provides flexible applications in spintronics. All the calculations demonstrate 100% spin polarized bands around the Fermi level for these MLs. Combining the semiconducting energy gap and the fully spin polarized valence and conduction bands in a single-layer [Formula Omitted], this new type 2D magnetic semiconductor shows great potential in future spintronics applications.