Dresden 2014 – scientific programme
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DS: Fachverband Dünne Schichten
DS 45: Poster IV: One-Dimensional Metals: Reality or Fiction
DS 45.10: Poster
Thursday, April 3, 2014, 16:00–19:00, P1
Spin-Polarization and Spin-Orbit Coupling in Au-Induced Atom Chains on High-Index Silicon Surfaces — •Julian Aulbach1, Jörg Schäfer1, Steven C. Erwin2, Sebastian Meyer1, Lenart Dudy1, Bartosz Slomsik3, Gabriel Landolt3, Hugo Dil3, and Ralph Claessen3 — 1Physikalisches Institut and Röntgen Center for Complex Materials Systems (RCCM), Universität Würzburg, Germany — 2Naval Research Laboratory, Washington DC, USA — 3Paul Scherrer Institut, Villigen, Switzerland
Atoms can form chain-like architectures by self-assembly on various semiconductor surfaces. Such may offer physical realizations of 1D electronic ground states like Peierls instabilities or Tomonaga-Luttinger liquids. Here we report on Au-stabilized nanowires on a high-index silicon substrate, namely Si(553). The two chain types present in that system, one built by Au and one by Si atoms, develop two- and threefold periodicities at low temperatures, which were previously assigned to Peierls instabilities. However, our results from scanning tunneling microscopy and spectroscopy are in astounding agreement with the Si(553)-Au ground state predicted by density-functional theory , where every third Si atom is spin polarized [1]. Moreover, the structural model [2] suggests strong spin-orbit coupling for the Au chains. Using spin- and angle-resolved photoemission we find direct evidence for such a spin-splitting in both Au-induced bands, rendering this system an intriguing 1D material with spin ordering in real and reciprocal space.
[1] J. Aulbach et al., Phys. Rev. Lett. 111, 137203 (2013).
[2] S. C. Erwin and F. J. Himpsel, Nature Commun. 1, 58 (2010).