Structural, electronic and magnetic properties of transition metal atom-doped ZnS dilute magnetic semiconductors: A first-principles study

- A single V, Cr, Fe or Ni (Mn or Co) atoms doped ZnS are magnetic HM (magnetic semiconductor).
- Two V, Cr or Ni (two Mn or Co) atoms doped ZnS are FM HM (AFM semiconductor).
- Two Fe atoms doped ZnS are AFM metal (FM HM) at the nearest (farther) separations.

The spin-polarized first-principles calculations are performed to study the structural, electronic and magnetic properties of a single and two identical transition metal (TM) atoms X (X = V, Cr, Mn, Fe, Co and Ni) doped ZnS dilute magnetic semiconductors (DMS). The single V-, Cr-, Fe- and Ni-doped ZnS systems exhibit the magnetic half-metallic (HM) characters, while Mn- and Co-doped ZnS systems display magnetic semiconducting characters. For two identical TM atoms doped ZnS systems, the two identical V, Cr and Ni atoms are in a ferromagnetic (FM) coupling under the double-exchange (DE) mechanism, leading V-, Cr- and Ni-doped ZnS systems to be HM with FM coupling. While two identical Mn- and Co-doped ZnS systems are semiconductors with antiferromagnetic (AFM) coupling consisting with the superexchange (SE) mechanism. Specifically, two identical Fe atoms display a competition between the SE and DE mechanisms. The Zn70Fe2S72 system is metal with AFM coupling at the nearest separation of two Fe atoms while HM with FM coupling at the farther separations of two Fe atoms.

The 3 × 2 × 3 supercell containing 72 formula units of zincblende ZnS. Red (Green) balls represent the S (Zn) atoms. One TM atom or two identical TM atoms X (X = V, Cr, Mn, Fe, Co or Ni) to substitute for one Zn atom at position 0 or two Zn atoms at positions 0 and i (i = 1, 2, 3 or 4).