Positron surface state as a spectroscopic probe for characterizing surfaces of topological insulator materials

Abstract

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 new technique for characterizing these states. Firm experimental evidence for the existence of a positron surface state near Bi${}_2$Te${}_2$Se with a binding energy of $E_b=2.7\pm 0.2\text{eV}$ 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 shows the feasibility to detect their spin-texture through the use of spin-polarized positron beams.

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Cited by in corpus (4)

• Nature of the positron state in CdSe quantum dots
• A multi-stop time-of-flight spectrometer for the measurement of positron annihilation-induced electrons in coincidence with the Doppler-shifted annihilation gamma photon
• Positron Induced Electron Emission from Graphite
• Identification of Auger mechanisms responsible for low energy electron emission from graphene on copper using Auger-gamma coincidence spectroscopy