%0 Journal Article
%A Esat, Taner
%A Deilmann, Thorsten
%A Lechtenberg, Benedikt
%A Wagner, Christian
%A Krüger, Peter
%A Temirov, Ruslan
%A Anders, Frithjof B.
%A Rohlfing, Michael
%A Tautz, Frank Stefan
%T Transfering spin into an extended π orbital of a large molecule
%J Physical review / B
%V 91
%N 14
%@ 1098-0121
%C College Park, Md.
%I APS
%M FZJ-2015-02781
%P 144415
%D 2015
%X By means of low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS), we have investigated the adsorption of single Au atoms on a PTCDA monolayer physisorbed on the Au(111) surface. A chemical reaction between the Au atom and the PTCDA molecule leads to the formation of a radical that has an unpaired electron in its highest occupied orbital. This orbital is a π orbital that extends over the whole Au-PTCDA complex. Because of the large Coulomb repulsion in this orbital, the unpaired electron generates a local moment when the molecule is adsorbed on the Au(111) surface. We demonstrate the formation of the radical and the existence of the local moment after adsorption by observing a zero-bias differential conductance peak that originates from the Kondo effect. By temperature dependent measurements of the zero-bias differential conductance, we determine the Kondo temperature to be TK=(38±8)K. For the theoretical description of the properties of the Au-PTCDA complex we use a hierarchy of methods, ranging from density functional theory (DFT) including a van der Waals correction to many-body perturbation theory (MBPT) and the numerical renormalization group (NRG) approach. Regarding the high-energy orbital spectrum, we obtain an excellent agreement with experiments by both spin-polarized DFT/MBPT and NRG. Moreover, the NRG provides an accurate description of the low-energy excitation spectrum of the spin degree of freedom, predicting a Kondo temperature very close to the experimental value. This is achieved by a detailed analysis of the universality of various definitions of TK and by taking into account the full energy dependence of the coupling function between the molecule-metal complex and the metallic substrate.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000353123800002
%R 10.1103/PhysRevB.91.144415
%U https://juser.fz-juelich.de/record/189751