Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 32: Surface Magnetism and Spin Phenomena

O 32.6: Poster

Tuesday, March 17, 2015, 18:15–21:00, Poster A

Surface states on Fe(110) - exploring their spin, decay rates, and magnetic linear dichroism — Beatrice Andres, Marc Christ, •Marko Wietstruk, and Martin Weinelt — Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin

Investigating iron (Fe) may seem old-fashioned but still it exhibits an exotic electronic band structure regarding it’s spin dependence. The large exchange splitting combined with hybridization of s, p, and d states results in totally different conditions for the formation of majority and minority surface-states [1]. In contrast to the well-known bulk band structure, very few studies on surface states have been performed. Some show quasiparticle renormalization in the surface states due to electron-magnon coupling [2,3].

We study the surface band structure on Fe/W(110) in a spin- and time-resolved one- and two-photon-photoemission experiment. On the one hand, we directly probe the occupied electronic structure with the fourth harmonic (6 eV) of a Ti:Sa laser. On the other hand, we use the fundamental (1.65 eV) and third harmonic (5 eV) to probe unoccupied image-potential states and investigate their spin-dependent decay rates. We find two occupied minority surface features crossing the Fermi level at ≈ 0.1 Å⁻¹ in Γ-H direction. These two minority features show a magnetic-linear-dichroic contrast (MLD) of opposite sign indicating different symmetries.

[1] Jürgen Braun, Phys. Rev. B 65, 184412 (2002)

[2] Jörg Schäfer, Phys. Rev. Lett. 92, 097205 (2004)

[3] Jörg Schäfer, Phys. Rev. B 72, 155115 (2005)