Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 21: Electronic Structure and Spin-Orbit Interaction I
O 21.11: Vortrag
Montag, 11. März 2013, 18:30–18:45, H42
Dirac-cone-like surface state in W(110): Dispersion, spin texture, and photoemission from first principles — Hossein Mirhosseini1, •Markus Flieger2, and Jürgen Henk2 — 1Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany — 2Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
We report on a theoretical study of a dz2 surface state at the tungsten (110) surface, addressing in detail the spin-resolved electronic structure as well as photoemission spectroscopy. In agreement with recent experiments [1], this surface state shows a strongly anisotropic dispersion: In the H–Γ–H direction of the surface Brillouin zone, it disperses linearly but becomes flattened along the N–Γ–N direction. The ab initio calculated spin texture agrees with the one derived from a model Hamiltonian; due to two-fold surface symmetry and time-reversal symmetry, the out-of-plane spin polarization vanishes. The photoemission intensities depend sensitively on the polarization of the incident light, because of the orbital composition of the surface state. The photoelectrons become spin-polarized out-of-plane, which is attributed to breaking the time-reversal symmetry by the excitation process.
[1] K. Miyamoto et alii, Phys. Rev. Lett. 108 (2012) 066808; eidem, Phys. Rev. B 86 (2012) 161411(R).