Response of the Shockley surface state to an external electrical field: A density-functional theory study of Cu(111)
| Autor: | Berland, K., Einstein, T. L., Hyldgaard, P. |
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| Rok vydání: | 2011 |
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| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.85.035427 |
| Popis: | The response of the Cu(111) Shockley surface state to an external electrical field is characterized by combining a density-functional theory calculation for a slab geometry with an analysis of the Kohn-Sham wavefunctions. Our analysis is facilitated by a decoupling of the Kohn-Sham states via a rotation in Hilbert space. We find that the surface state displays isotropic dispersion, quadratic until the Fermi wave vector but with a significant quartic contribution beyond. We calculate the shift in energetic position and effective mass of the surface state for an electrical field perpendicular to the Cu(111) surface; the response is linear over a broad range of field strengths. We find that charge transfer occurs beyond the outermost copper atoms and that accumulation of electrons is responsible for a quarter of the screening of the electrical field. This allows us to provide well-converged determinations of the field-induced changes in the surface state for a moderate number of layers in the slab geometry. Comment: 11 pages, 6 figures, 4 tables; accepted for publication by Phys. Rev. B; changes from v1 in response to referee comments, esp. to Sections I and V.B (inc. Table 4), with many added references, but no change in results or conclusions |
| Databáze: | arXiv |
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