First-principles study of the heavy metal atoms X (X=Au, Hg, Tl or Pb) doped monolayer WS_2

摘要

The heavy metal atoms X (X = Au, Hg, Tl or Pb) doped monolayer WS_2 systems have been studied by using the spin-polarized first-principles calculations. Although pure monolayer WS2 system is a nonmagnetic semiconductor with a direct band gap of 1.820 eV, the Au and Hg atoms doped monolayer WS2 systems change to half-metal (HM) ferromagnets with the total magnetic moments 0.697 and 1.776 μ_B as well as the smaller spin-down gaps 0.605 and 0.527 eV, respectively, while the Tl and Pb atoms doped monolayer WS_2 systems change to magnetic metal with the total magnetic moment 0.584 μ_B and a nonmagnetic metal. From the minimization of the formation energy, we find that it is easy to incorporate these heavy metal atoms into monolayer WS_2 system under S-rich condition, especially for the Au doped monolayer WS_2 system not only easily to be formed but also a HM ferromagnet, and thus the best candidate used in the spintronic devices.