Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 95: Metallic nanowires on the atomic scale (DS with O)

O 95.5: Talk

Friday, March 20, 2015, 10:45–11:00, H 2032

Observation of correlated spin-orbit order in a strongly anisotropic quantum wire system — •Christian Brand¹, Monika Jäger¹, Herbert Pfnür¹, Gabriel Landolt^2,3, Hugo Dil^2,4, Stefan Muff^2,4, Tanmoy Das⁵, and Christoph Tegenkamp¹ — ¹Institut für Festkörperphysik, Leibniz Universität Hannover, Germany — ²Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland — ³Physik-Institut, Universität Zürich, Switzerland — ⁴Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, Switzerland — ⁵Theoretical Division, Los Alamos National Laboratory, USA

The surface of 1.31 ML Pb on Si(557) reveals a highly anisotropic wire ensemble structure becoming insulating in the direction across the wires when cooling below 78 K (2D/1D transition) as seen by surface transport. The delicate interplay between the superlattice structure, band filling, and extremely large Rashba type spin-orbit interaction results in a highly correlated entangled spin- and charge-state. The spin texture close to the Fermi surface is found to be alternating and equidistant, thus Fermi nesting occurs in between bands with the opposite helicity. Furthermore, the interwire coupling has been gradually changed by adsorption of excess Pb nucleating preferentially at the step edges. The analysis of spin-resolved momentum distribution curves shows that Fermi nesting is preserved up to 0.2 ML. Both the spin-dephasing seen in ARPES as well as the increase of the spin-orbit scattering rates from former magneto transport measurements is quantitatively explained in the framework of a spin-orbit density wave.