Energetics, electronic and magnetic properties of monolayer WSe2 doped with pnictogens, halogens and transition-metal (4d, 5d) atoms: An ab-initio study

Abstract

Abstract Spin-polarized density-functional theory calculations with generalized gradient approximation (GGA) as the exchange-correlation functional have been performed to study the energetics, electronic and magnetic properties of the monolayer WSe2 doped with atomic impurity atoms. We have considered selenium (Se) substitution by pnictogens (N, P, As, Sb and Bi) or halogens (F, Cl, Br, I and At). We also investigate tungsten (W) atom substitution by a transition-metal (TM) of 4d (Nb, Rh) or 5d (Lu, Hf, Ta, Re, Os, Ir, Pt, Au, and Hg). Our calculated values of formation energies suggest that halogens are more easily incorporated in WSe2 under W-rich conditions while Se-rich conditions is energetically more favourable for metal doping. Also, we show that the WSe2 monolayer doped by pnictogens may results in p-type doping while halogens dopants may cause n-type doping of the WSe2 monolayer. Metallic dopants of Re, Os, Ir and Rh induce n-type doping while Lu, Hf, Ta, and Nb induce p-type doping in the WSe2. In general, we deduce that a TM dopant, the d-orbital of which is less occupied than that of substituted W, is a promising candidate for performing p-type doping. Furthermore, we found that some dopants induce magnetization of the WSe2. Our findings suggest that I, Ir and Au dopants may induce half-metallicity in the monolayer WSe2, which indicates that I-WSe2, Ir-WSe2 and Au-WSe2 chemical systems could be quite important for spintronics applications that rely on spin-filtering.