Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 116: Topological insulators (organized by MA)

HL 116.5: Talk

Friday, April 4, 2014, 10:45–11:00, HSZ 04

Spin-dependent unoccupied electronic structure of the topological insulator Sb₂Te₃ — •Anna Zumbülte¹, Anke B. Schmidt¹, Markus Donath¹, Peter Krüger², Gregor Mussler³, and Detlev Grützmacher³ — ¹Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Germany — ²Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Germany — ³Peter Grünberg Institut, Forschungszentrum Jülich, Germany

Studies on three-dimensional topological insulators focus mainly on the well-known systems of Bi₂Se₃ and Bi₂Te₃ and the related ternary compounds. Theoretical predictions of chalcogenides as topological insulators with a single Dirac cone [1] include an additional compound, Sb₂Te₃. There, due to p-type doping of the available samples, the Dirac point lies above the Fermi level, making it inaccessible to photoemission experiments unless the surface is modified with an adsorbate [2]. Consequently, the electronic structure of this system has been left almost unstudied.

We present spin- and angle-resolved inverse-photoemission measurements of the unoccupied electronic states of Sb₂Te₃. In addition to the Dirac state, further spin-dependent features have been obtained which show a distinct Rashba splitting. The experimental data will be discussed along with bandstructure calculations.

[1] H. Zhang et al., Nat. Phys. 5, 438 (2009)

[2] C. Seibel et al., Phys. Rev. B 86, 161105 (2012)