Organic charge-transfer salts have shown interesting physical properties based on the interplay of electronic correlation effects with low dimensionality and geometric frustration. The main subject area of this project is the investigation of electronic correlation effects in organic charge-transfer salts using scanning tunneling microscopy (STM) and spectroscopy (STS) allowing for a combination of lateral resolution and spectroscopy. We will explore the single particle density-of-states in the ground state and its temperature dependence across the superconducting phase transition of quasi-2D-(BEDT-TTF)2X. Single crystals of these materials, which have shown to exhibit electronic correlation effects, will be studied. An in-situ cleavage will be used as a method to obtain clean surfaces in-situ in ultrahigh vacuum. In-situ deposition of ultra-thin films using mild thermal evaporation from single crystal material provides a second approach for preparation of clean surfaces. Novel charge-transfer salts with potentially large electronic correlation effects, consisting of building blocks of organic molecules with Pi-conjugated ring structures, are fabricated by co-deposition in ultrahigh vacuum. Varying composition and ligand coordination the electronic structure is tailored aiming at a detailed understanding of electronic correlation in organic salts. Future technical applications require an understanding of the interface between organic salts and a metallic electrode. Gap size and pinning of the levels to the Fermi edge of a metal electrode govern the charge injection effciency and the electronic transport properties that is studied in this project by scanning tunneling spectroscopy.

geändert am 09. Juni 2011  E-Mail: Webmasterwillkomm@physik.uni-frankfurt.de