Density Functional Theory Study of the Electronic Structures of Galena

Abstract

In this study, the electronic structure of the galena surface was investigated using the first-principle calculation. The results of band structure, density of states, Mulliken population distribution, and frontier orbital analysis showed that galena was the p-type semiconductor of the direct band gap. During the formation of galena crystals, the 3p orbital of the S and the 6p orbital of the Pb played a primary role. Additionally, S atoms in galena quickly lose electrons and are oxidized, while Pb readily reacts with anions. The results of surface structure and electronic properties, such as surface relaxation, surface state energy levels, electronic density of states, and atomic charge distribution showed that the electronics in the 6p orbital of the Pb are transferred to the 3p orbital of the S in galena crystal. They caused the change of atomic valence states in lattice surfaces. The total electron number of the outermost surface layer was also higher than the bulk, giving the galena surface the properties of electron enrichment. This research is of great significance for developing new galena flotation reagents and for further in-depth exploration of the adsorption of reagents on the galena surface.

Elucidating the Mechanisms of the Large Stokes Shift in Isolated and Coupled PbS Quantum Dots

“…The calculated band gap of PbS bulk material and QDs agrees well with that of the previous works. 43,44 As shown in Figures S15 and S16, the conduction band edge state (CBES) is dominated by Pb p-orbitals, while the valence band edge states (VBESs) mainly arise from the overlap of S p-orbitals. Figure S17 shows the electron density distributions of h 1 , h 0 , e 0 , and e 1 energy levels for Pb 16 S 16 , Pb 28 S 28 , Pb 44 S 44 , and Pb 68 S 68 .…”