Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 21: Clean surfaces: Metals, semiconductors, oxides and insulators II
O 21.3: Vortrag
Montag, 14. März 2011, 17:45–18:00, WIL B122
(contribution withdrawn) Spin-orbit effects in two-electron emission from ferromagnets — •Franz Giebels1,2, Herbert Gollisch1, and Roland Feder1,2 — 1Theoretische Festkörperphysik,Universität Duisburg-Essen, 47048 Duisburg, Germany — 2Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
The momentum-resolved detection of correlated electron pairs, which are ejected from ferromagnetic
surfaces upon impact of spin-polarized low-energy electrons, yields information on
exchange and correlation effects and on the spin-resolved electronic surface structure [1].
Furthermore, spin-orbit coupling (SOC) effects have been found experimentally [2].
We present a theoretical formalism for
electron-induced electron pair emission from ferromagnetic surfaces,
which is based on a Dirac equation with an effective magnetic field.
Exchange interaction and SOC are thus incorporated simultaneously.
The formalism has been implemented in a computer code.
We present typical numerical results, which demonstrate the manifestation of
SOC in pair emission energy and angular distributions.
Depending on the relative orientations of the primary electron spin polarization,
the reaction plane and the magnetization direction of the surface system,
SOC effects may dominate over exchange effects or vice versa.
In two-dimensional momentum distributions, SOC reduces the rotation symmetry
of the exchange-correlation hole, e.g. for cubic (001) surfaces from four-fold to
two-fold.
[1] F. Schumann et al., Phys. Rev. Lett. 104, 087602 (2010)
[2] S. Samarin et al., Phys. Rev. Lett. 97, 096402 (2006)