Positron surface state as a spectroscopic probe for characterizing surfaces of topological insulator materials
Author(s)Callewaert, Vincent; Shastry, K.; Saniz, Rolando; Makkonen, Ilja; Barbiellini, Bernardo; Assaf, Badih A.; Partoens, Bart; Bansil, Arun; Weiss, A. H.; Heiman, Donald E.; Moodera, Jagadeesh; ... Show more Show less
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Topological insulators are attracting considerable interest due to their potential for technological applications and as platforms for exploring wide-ranging fundamental science questions. In order to exploit, fine-tune, control, and manipulate the topological surface states, spectroscopic tools which can effectively probe their properties are of key importance. Here, we demonstrate that positrons provide a sensitive probe for topological states and that the associated annihilation spectrum provides a technique for characterizing these states. Firm experimental evidence for the existence of a positron surface state near Bi2Te2Se with a binding energy of Eb=2.7±0.2eV is presented and is confirmed by first-principles calculations. Additionally, the simulations predict a significant signal originating from annihilation with the topological surface states and show the feasibility to detect their spin texture through the use of spin-polarized positron beams.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Plasma Science and Fusion Center; Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology)
Physical Review B
American Physical Society
Callewaert, Vincent, K. Shastry, Rolando Saniz, Ilja Makkonen, Bernardo Barbiellini, Badih A. Assaf, Donald Heiman, et al. “Positron Surface State as a Spectroscopic Probe for Characterizing Surfaces of Topological Insulator Materials.” Physical Review B 94, no. 11 (September 6, 2016).
Final published version