Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 31: Focus Session: Dirac fermions in solid-state systems (HL, jointly with TT)
HL 31.4: Topical Talk
Tuesday, March 12, 2013, 11:15–11:45, H2
Lifetime broadening of topological surface states with and without magnetic moments — •Oliver Rader1, Markus Scholz1, Jaime Sánchez-Barriga1, Andrei Varykhalov1, Dmitry Marchenko1, Emile Rienks1, Andrey Volykhov2, and Lada Yashina2 — 1Helmholtz-Zentrum Berlin — 2Moscow State University
The lifetime broadening of the angle-resolved photoemission signal from the surface states of Bi2Se3 and Bi2Te3 is studied. It is revealed that hexagonal warping in Bi2Te3 introduces an anisotropy for electrons propagating along Γ-K and Γ-M. Moreover, we show that the electron-phonon coupling strength is substantial and in good agreement with theoretical predictions. The small Fermi surface is believed to limit the number of phonon modes for electron scattering. In line with this, the imaginary part of the self-energy from the surface state electrons declines with higher binding energies. In addition, we find that Fe surface impurities have a much stronger influence on the lifetimes as compared to Ag. This is independent of the sign of the doping which is p-type when Fe is deposited at low temperature.