Depth dependence of vacancy formation energy at (100), (110), and (111) Al surfaces: A first-principles study
| Autor: | Gupta, S. S., Van Huis, M. A., Sluiter, M. H F, Dijkstra, M., Soft Condensed Matter and Biophysics, Sub Soft Condensed Matter, Debye Institute |
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| Přispěvatelé: | Soft Condensed Matter and Biophysics, Sub Soft Condensed Matter, Debye Institute |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Surface (mathematics)
Materials science Condensed matter physics Plane (geometry) Nanoparticle chemistry.chemical_element 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials Metal Sphere packing Nanocrystal chemistry Aluminium Vacancy defect visual_art 0103 physical sciences Electronic visual_art.visual_art_medium Optical and Magnetic Materials 010306 general physics 0210 nano-technology |
| Zdroj: | Physical review. B, Condensed matter and materials physics, 93(8). American Physical Society Physical Review B (Condensed Matter and Materials Physics), 93(8) |
| ISSN: | 1098-0121 |
| Popis: | Vacancy defects are known to play an important role in the structural and chemical properties of metallic and semiconductor nanoparticles. Here, we investigate the likelihood of vacancy formation at the surface, in the subsurfaces, and in the interior of a model system of Al nanocrystals. The depth dependence of the vacancy formation energy (VFE) in 14-17 layered low-indexed surfaces of aluminium is studied using LDA, PBE, and PBEsol exchange-correlation functionals. Within a depth of two subsurface layers, the functionals make a transition from a similar description of surfaces to the differences in VFEs observed in bulk Al. The VFE converges to the bulk value within 0.01 eV beyond a maximum depth of 3-6 atomic layers, depending on the crystallographic surface plane. We find that the different convergence behaviors are related to the relaxations of atomic planes, normal to the surface, which in turn depend on the packing density of these surfaces. For the (111) subsurfaces, surprisingly, the defect formation energies are found to be higher than that of bulk Al, which is related to the hindered relaxations in its close-packed atomic planes. Although our results predict considerably lower VFE for the topmost layers of all the surfaces, the likelihood of forming a vacancy in the immediate subsurfaces of multifaceted Al nanoparticles is predicted to be lower than in bulk Al, which is in contrast to expectation. |
| Databáze: | OpenAIRE |
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