Title
Accurate description of the van der Waals interaction of an electron-positron pair with the surface of a topological insulatorAccurate description of the van der Waals interaction of an electron-positron pair with the surface of a topological insulator
Author
Faculty/Department
Faculty of Sciences. Chemistry
Faculty of Sciences. Physics
Research group
Electron microscopy for materials research (EMAT)
Condensed Matter Theory
Publication type
conferenceObject
Publication
Bristol,
Subject
Physics
Chemistry
Source (journal)
Journal of physics : conference series. - Bristol
Volume/pages
505(2014), 4 p.
ISSN
1742-6588
Article Reference
012002
ISI
000338216500002
Carrier
E-only publicatie
Target language
English (eng)
Full text (Publishers DOI)
Affiliation
University of Antwerp
Abstract
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.
E-info
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