Figure 1

Band structure and density of states for 3p orbitals of S atom and 4d orbitals of Pd atom in Pd2S4 structure: (a–e) without vacancy defect, (f–j) arising from defects in S atoms, (k–o) arising from defects in Pd atoms, (p) top view of Pd2S4 structure with the position of vacancy defect for S (No. 1) and Pd (No. 2) atoms, (q) side view of Pd2S4 structure, and (r) electrons located in 4d orbitals of Pd+4  cation in strong and weak crystal fields.