Abstract
Chalcopyrite (CuFeS2) surfaces are of major interest for copper exploitation in aqueous solution, called leaching. Since leaching is a surface process knowledge of the surface structure, bonding pattern and oxidation states is important for improving the efficiency. At present such information is not available from experimental studies. Therefore a detailed computational study of chalcopyrite surfaces is performed. The structures of low-index stoichiometric chalcopyrite surfaces {hkl} h, k, l ∈ {0, 1, 2} have been studied with density functional theory (DFT) and global optimization strategies. We have applied ab initio molecular dynamics (MD) in combination with simulated annealing (SA) in order to explore possible reconstructions via a minima hopping (MH) algorithm. In almost all cases reconstruction involving substantial rearrangement has occurred accompanied by reduction of the surface energy. The analysis of the change in the coordination sphere and migration during reconstruction reveals that S-S dimers are formed on the surface. Further it was observed that metal atoms near the surface move toward the bulk forming metal alloys passivated by sulfur. The obtained surface energies of reconstructed surfaces are in the range of 0.53–0.95 J/m2.
Original language | English |
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Pages (from-to) | 1-9 |
Number of pages | 9 |
Journal | Surface Science |
Volume | 669 |
Early online date | 8 Nov 2017 |
DOIs | |
Publication status | Published - 1 Mar 2018 |
Funding
The authors gratefully acknowledge the PC 2 Paderborn Center for Parallel Computing for funding this project by providing computing time on the OCuLUS system. We also acknowledge the DAAD funding for the project entitled ‘Theoretical Investigation of Chalcopyrite Surfaces’ with project ID 57060317 .
Keywords
- Chalcopyrite
- Density functional theory
- Global optimization
- Minima hopping
- Surface energy
- Surface reconstruction
ASJC Scopus subject areas
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry