A DFT study of the effect of natural impurities on the electronic structure of galena

A systematic study of the electronic structures of natural galena containing ten typical kinds of impurities is performed by the density-functional theory (DFT). Mn, As, Bi, In and Sb impurities make the Fermi level shift to the higher energy level, while Ag, Cu and Tl impurities make the Fermi level shift to the lower energy level. Mn, In, Sb, Zn and Tl impurities result in a decrease in the Mulliken charge of the Pb atom and might decrease the ionicity of galena, whereas Ag, Cu, Bi, As and Cd impurities lead to an increase in that of the Pb atom. The frontier orbital calculations show that Sb and Mn impurities might lead to the over-oxidation of galena, and thus are unfavorable for the flotation of galena.

Research Highlights
► The supercell model of impurity-bearing galena was constructed adopting quantum chemistry simulation, and the calculations of electronic properties of natural galena containing ten kinds of impurities were performed.
► Mn, As, Bi, In and Sb impurities make the Fermi level shift to the higher energy level, while Ag, Cu and Tl impurities make the Fermi level shift to the lower energy level.
► Mn, In, Sb, Zn and Tl impurities result in the decreased Mulliken charge of the Pb atom and might decrease the ionicity of galena, whereas Ag, Cu, Bi, As and Cd impurities lead to an increase in that of the Pb atom.
► The frontier orbital calculations show that Sb and Mn impurities might lead to the over-oxidation of galena, and thus are unfavorable for the flotation of galena.