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Accurate description of the van der Waals interaction of an electron-positron pair with the surface of a topological insulator
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| Abstract |
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| Positrons can be trapped in localized states at the surface of a material, and thus quite selectively interact with core or valence surface electrons. Hence, advanced surface positron spectroscopy techniques can present the ideal tools to study a topological insulator, where surface states play a fundamental role. We analyze the problem of a positron at a TI surface, assuming that it is a weakly physisorbed positronium (Ps) atom. To determine if the surface of interest in a material can sustain such a physisorption, an accurate description of the underlying van der Waals (vdW) interaction is essential. We have developed a first-principles parameterfree method, based on the density functional theory, to extract key parameters determining the vdW interaction potential between a Ps atom and the surface of a given material. The method has been successfully applied to quartz and preliminary results on Bi2Te2Se indicate the existence of a positron surface state. We discuss the robustness of our predictions versus the most relevant approximations involved in our approach. | |
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English
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| Source (journal) |
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Journal of physics : conference series. - Bristol |
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| Publication |
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Bristol : 2014
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| ISSN |
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1742-6588 [print]
1742-6596 [online]
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| Volume/pages |
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505(2014), 4 p.
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| Article Reference |
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012002
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| ISI |
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000338216500002
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E-only publicatie
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| Full text (publisher's version - intranet only) |
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