Dresden 2014 – wissenschaftliches Programm

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SYOM: Symposium One-dimensional Metals: Reality or Fiction

SYOM 2: Posters: One-Dimensional Metals: Reality or Fiction (jointly organized by DS, HL, O, TT)

SYOM 2.9: Poster

Donnerstag, 3. April 2014, 16:00–19:00, P1

Evidence of Spin-Orbit Density Waves in Atomic Pb-Wires on Si(557) — •Christian Brand¹, Daniel Lükermann¹, Herbert Pfnür¹, Gabriel Landolt², Hugo Dil^2,3, and Christoph Tegenkamp¹ — ¹Institut für Festkörperphysik, Leibniz Universität Hannover, Germany — ²Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland — ³Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, Switzerland

Growth of 1.3 monolayers Pb on Si(557) results in a highly anisotropic wire ensemble structure which undergoes a 2D/1D transition when cooling below 78 K as seen by surface sensitive transport measurements. In particular, the system becomes insulating in the direction across the wires. We will show that the mutual interplay between superlattice structures, band filling factors, and spin-orbit coupling results in a highly correlated electronic spin and charge state. By means of spin- and angle-resolved photoemission spectroscopy (SR-ARPES), supplemented by LEED and STM, the spin texture close to the Fermi surface was found to be alternating and equidistant; thus, Fermi nesting occurs in between bands with the same spin texture, giving rise to spin spirals in the direction across the wires. An out-of-phase superposition of both Rashba channels is manifested by an extraordinary large Rashba splitting of Δ k₀ = 0.2 Å⁻¹ = g/2, where g is a reciprocal lattice vector defined by the interwire distance and fits into the model of spin-orbit density waves in antiferromagnetically ordered chain structures. The implications towards spin-polarized transport along the wires will be discussed.