Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 8: Electronic Structure and Spin-Orbit Interaction I

O 8.2: Talk

Monday, March 31, 2014, 10:45–11:00, GER 38

Spin-flip scattering in the surface bands of BiAg₂/Ag(111) — •Gustav Bihlmayer¹, Lydia El-Kareh², Matthias Bode², and Stefan Blügel¹ — ¹Peter Grünberg Institut and Institute of Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany — ²Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany

Since its discovery, the surface alloy BiAg₂/Ag(111) has attracted considerable attention due to the ’giant Rashba’ splitting in the occupied surface bands. Recently, also the unoccupied part of the spectrum was investigated by scanning tunneling microscopy. But, although theory predicted a rather complex spin-texture of these bands [1], the quasiparticle interference patterns seem compatible with a conventional Rashba-type spin-polarization of these bands [2]. Close examination of the spin- and orbital resolved bandstructures obtained by density functional theory show, that the orbital structure allows spin-flip scattering processes that can reconcile experimental evidence with theoretical predictions. Our calculations and experiments show that this behavior is not only characteristic for the Bi-based surface alloy, also in the PbAg₂/Ag(111) system these spin-flip scattering events are observed. The same mechanism also blocks quasiparticle interference in forward scattering, while other scattering events are explicitly forbidden by time-reversal symmetry.
G. Bihlmayer et al., Phys. Rev. B 75, 195414 (2007)
L. El-Kareh et al., Phys. Rev. Lett. 110, 176803 (2013)