Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Molecular Nanostructures

O 59.8: Vortrag

Donnerstag, 28. Februar 2008, 11:15–11:30, MA 041

Structure and Charge Transfer in Metal-TCNQ Complexes on Cu (100) — •Tzu-Chun Tseng¹, Steven L. Tait¹, Xiong Liu¹, Nian Lin¹, and Klaus Kern^1,2 — ¹Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany — ²Institut de Physique des Nanostructures, Ecole Polytechnique Fédéral de Lausanne (EPFL), 1015 Lausanne, Switzerland

Organic-based alternatives to conventional magnets offer the possibility to form self-organized nanometer-scale structures at surfaces with specific magnetic properties. For example, coordination compounds of metal ions (M) with the organic molecule 7,7,8,8-tetracyanoquinodimethane (TCNQ) in solution have been shown recently to have a high magnetic ordering temperature for large M:TCNQ ratios (R. Jain et al., Nature 445 (2007) 291-294). A critical issue for the development of metal-organic structures in magnetic or electronic applications is the relationship of electronic configuration to physical structure. Here we correlate structural information of 2D M-TCNQ (M = Mn, Fe, Co, Ni, Cu) networks from scanning tunneling microscopy and low energy electron diffraction with charge transfer information obtained by X-ray photoemission spectroscopy. M-TCNQ mixtures at Cu(100) self-organize into ordered structures, whose coordination ratio and domain size depend strongly on the choice of metal. XPS results identify distinct core level shifts in N 1s spectra of M-TCNQ for 2D coordination to different metal centers compared to neutral TCNQ.