TY  - JOUR
AU  - Esat, Taner
AU  - Deilmann, Thorsten
AU  - Lechtenberg, Benedikt
AU  - Wagner, Christian
AU  - Krüger, Peter
AU  - Temirov, Ruslan
AU  - Anders, Frithjof B.
AU  - Rohlfing, Michael
AU  - Tautz, Frank Stefan
TI  - Transfering spin into an extended π orbital of a large molecule
JO  - Physical review / B
VL  - 91
IS  - 14
SN  - 1098-0121
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2015-02781
SP  - 144415
PY  - 2015
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000353123800002
DO  - DOI:10.1103/PhysRevB.91.144415
UR  - https://juser.fz-juelich.de/record/189751
ER  -