Increasing the dimensionality of the Luttinger-electron-system Au/Ge(001) by molecular bridges, studied by scanning tunneling spectroscopy

• Applicant: Professor Dr. René Eugen Matzdorf
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2013 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 235799445

Exotic states of correlated electron systems are of strong interest in current research. In many materials, localization of electrons on certain lattice sites leads to strong correlations in all dimensions. In contrast, correlations are weak in many other materials, like the noble metals for example, because the electrons can move freely in the three dimensional metal. In these materials the reduction of dimensionality may increase correlations. Actually, in some quasi one dimensional systems a Tomanaga-Luttinger-Liquid (TLL) forms. In a collaboration with Prof. R. Claessen, PD J. Schäfer et al. at the University of Würzburg, we have investigated the system of gold chains on Ge(001). In gold, which is a weakly correlated metal as bulk material, a strongly correlated one dimensional electron system is formed due to reduction of dimensionality. For the first time the system offers the possibility to manipulate a TLL on the atomic scale, since the gold chains are accessible with the methods of surface science. Currently, Au/Ge(001) offers the possibility to investigate many open questions that were not accessible experimentally so far.In this project, the dimensionality shall be increased continously by placing single conducting bridges between the gold chains. As bridges, specially selected or even specially designed organic molecules shall be used. By selection of organic molecules with suitable anchor groups for the contact to gold, a suitable length for 1.6 nm distance between the chains and a suitable electron system for the transport of electrons at the fermi energy, we expect to have a controlled influence on the dimensionality of the electron system. The goal of the project is to investigate the transition from a 1D-TLL to a 2D-Fermi liquid, by placing local conducting bridges with different properties and at different densities between the atomic gold chains.

• DFG Programme: Research Grants