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Title
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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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Author
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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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Language
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English
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Source (journal)
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Journal of physics : conference series. - Bristol, 2004, currens
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Source (book)
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13TH INTERNATIONAL WORKSHOP ON SLOW POSITRON BEAM TECHNIQUES AND APPLICATIONS (SLOPOS13), 15-20 September, 2013, Munich, Germany
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Publication
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Bristol
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Institute of Physics Publishing
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2014
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ISSN
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1742-6588
[print]
1742-6596
[online]
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DOI
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10.1088/1742-6596/505/1/012002
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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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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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