Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 77: Electronic Structure and Spin-Orbit Interaction III
O 77.10: Vortrag
Donnerstag, 14. März 2013, 18:15–18:30, H33
Low-temperature superstructure of Au-induced atom chains on high-index silicon surfaces — •J. Aulbach1, J. Schäfer1, S.C. Erwin2, S. Meyer1, L. Dudy1, B. Slomski3, G. Landolt3, H. Dil3, and R. Claessen1 — 1Physikalisches Institut, Universität Würzburg, Germany — 2Naval Research Laboratory, Washington DC, USA — 3Paul Scherrer Institut, Villigen, Switzerland
Self-organized nanowires on high-index semiconductor substrates provide a versatile playground to scrutinize the low-temperature ground state of quasi-one-dimensional systems, such as a charge density wave (CDW) or a Tomonaga-Luttinger liquid. Here we report on Au nanowires on Si(553), where a structural model from density functional theory (DFT) [1] suggests strong spin-orbit coupling for the Au chains. Intriguingly, also antiferromagnetic spin order is proposed for the silicon structure along the terrace edges.
Scanning tunneling microscopy images of Au/Si(553) are found to be in astounding agreement with the structural model [1], including its periodicities. Moreover, tunneling spectroscopy measurements at low temperature indicate the absence of an energy gap. This does not support the picture of two coexisting CDWs, contrary to previous perception. Instead, the local density of states displays a distinctive structure which matches the spin-polarized Si step-edge state predicted by DFT. Finally, we briefly address the spin-orbit coupling in the Au bands using spin- and angle-resolved photoemission, providing direct evidence for a spin-splitting.
[1] S. C. Erwin and F. J. Himpsel, Nature Commun. 1, 58 (2010).