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

关联电子系统的奇异态是当前研究的热点。在许多材料中，电子在某些晶格位置上的局域化导致所有维度的强相关性。相比之下，在许多其他材料中，相关性很弱，例如贵金属，因为电子可以在三维金属中自由移动。在这些材料中，维数的降低可以增加相关性。实际上，在某些准一维系统中，形成Tomanaga-Luttinger-Liquid（TLL）。与R教授合作。在维尔茨堡大学的Claessen，PD J. Schäfer等人的研究中，我们研究了Ge（001）上的金链系统。金是一种弱关联的金属体材料，由于降维作用，形成了一个强关联的一维电子系统。该系统首次提供了在原子尺度上操纵TLL的可能性，因为金链可以用表面科学的方法来访问。目前，Au/Ge（001）为研究许多实验上尚无法解决的问题提供了可能性，在本项目中，将通过在金链之间放置单个导电桥来不断增加维数。作为桥，应使用特别选择或甚至特别设计的有机分子。通过选择具有合适的锚基团的有机分子与金接触，合适的长度为1.6 nm的链之间的距离和合适的电子系统在费米能量下的电子传输，我们希望有一个控制的影响的电子系统的维数。该项目的目标是研究从1D-TLL到2D-Fermi液体的转变，通过在原子金链之间放置具有不同属性和不同密度的局部导电桥。

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.