Dresden 2014 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 45: Poster IV: One-Dimensional Metals: Reality or Fiction

DS 45.15: Poster

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

Optical properties of gold and indium atom chains on Si(111) — •Fabian Hötzel¹, Olaf Skibbe¹, Eugen Speiser², and Annemarie Pucci¹ — ¹Kirchhoff Institute of Physics, Heidelberg University, Heidelberg, Germany — ²ISAS-Institute for Analytical Sciences, Department Berlin, Berlin, Germany

Optical properties of self-assembled gold atom chains on Si(111) are investigated by Fourier transform infrared spectroscopy in transmittance geometry. Reflection high energy electron diffraction patterns reveal two different domains of 5x2 reconstruction showing metallic behavior between 20 and 423K. Therefore a metal-to-insulator transition of this system can be excluded in this temperature range. The infrared absorption is proportional to the fraction of gold-reconstructed surface and higher at low temperatures. Transmittance spectra can be depicted by a Drude type dielectric function. The resulting sheet conductance is inversely proportional to temperature which emphasizes the metallic character of this system. By means of polarization dependent measurements the orientations of the two domains of gold chains can be identified. Reflectance anisotropy spectra of indium atom chains on the stepped Si(111) surface show an anisotropic interband transition at 1.9eV. The splitting of this feature at 40K along with structural changes of the LEED pattern confirms the metal-to-insulator transition at low temperatures caused by Peierls instability. This contribution is related to DFG-FOR1700.