Structural, electronic, magnetic, and optical properties of new TiXY (X = F and Cl; Y = S, Se and Te) Janus monolayers: A first-principles study

Abstract

Extensive investigations have been carried out to search for new multifunctional two-dimensional (2D) materials with intriguing electronic and magnetic properties. In this paper we investigate novel Janus monolayers using first-principles calculations, which may be created by halogenation of the titanium dichalcogenide (TiCh2) single layers. We employ the full-potential linearized augmented plane wave (FP-LAPW) method to solve the self-consistent Kohn–Sham equations. The exchange–correlation potentials are described with the Wu–Cohen scheme. Our simulations assert that the TiFSe, TiClS, and TiClSe monolayers show the half-metallicity, resulting from the metallic spin-up channel and semiconductor spin-down channel. In contrast the TiFS, TiFTe, and TiClTe layers exhibit metallic nature in both spin channels. Significant magnetization with total spin magnetic moments ranging from 0.812 to 1.010 μB may be obtained, which are produced mainly by the spin-polarization of the Ti-3d orbital. The absorption coefficient spectra suggest a wide band absorption from infrared to ultraviolet regimes, with large values of the order of 105/cm. Results obtained herein suggest that the TiXCh (X = F and Cl; Ch = S, Se and Te) may be prospective candidates for applications in nano spintronic and optoelectronic devices.