Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 15: Spin-Orbit Interaction at Surfaces II
O 15.4: Vortrag
Montag, 22. März 2010, 15:45–16:00, H38
Tuneable Hybridization between Rashba-split Surface States in BiAg2/Ag/Au(111) Trilayer Systems — •Hendrik Bentmann1, Frank Forster1, and Friedrich Reinert1,2 — 1Universität Würzburg, Experimentelle Physik VII, Am Hubland, D-97074 Würzburg, Germany — 2Forschungszentrum Karlsruhe, Gemeinschaftslabor für Nanoanalytik, D-76021 Karlsruhe, Germany
We have studied the surface states of a BiAg2 surface alloy grown on thin Ag films on Au(111) by angle-resolved photoelectron spectroscopy. In contrast to the case of the bulk Ag(111) substrate we find the spz-type and the pxpy-type surface state to be separated by a hybridization gap that is accompanied by a pronounced kink in the dispersion of the pxpy-type state. The size of the gap is tunable via the Ag film thickness, whereas the gap closes for higher coverages. Our observations are attributed to slight variations in the protrusion height of the Bi atom. We propose that these variations are induced by thickness-dependent partial charge densities of the Ag quantum well states in the topmost layer. According to previous calculations we anticipate an unconventional sign change of the spin polarization at the hybridization kink of the pxpy-type state [1,2].
[1] H. Mirhosseini, J. Henk, A. Ernst, S. Ostanin, C.T. Chiang, P. Yu,
A. Winkelmann, and J. Kirschner, Phys. Rev. B 79, 245428 (2009).
[2] G. Bihlmayer, S. Blügel, and E. V. Chulkov, Phys. Rev. B 75,
195414 (2007).