Journal Article

FZJ-2015-02781

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Transfering spin into an extended π orbital of a large molecule

Esat, T. (Corresponding Author)FZJ* ; Deilmann, T. ; Lechtenberg, B. ; Wagner, C.FZJ* ; Krüger, P. ; Temirov, R.FZJ* ; Anders, F. B. ; Rohlfing, M. ; Tautz, F. S.FZJ*

2015
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/8535  doi:10.1103/PhysRevB.91.144415

Abstract: 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.

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Contributing Institute(s):

1. Funktionale Nanostrukturen an Oberflächen (PGI-3)
2. John von Neumann - Institut für Computing (NIC)

Research Program(s):

1. 141 - Controlling Electron Charge-Based Phenomena (POF3-141) (POF3-141)
2. Nonequilibrium dynamics of quantum impurity systems close quantum phase transitions (hhb00_20130501) (hhb00_20130501)

Appears in the scientific report 2015

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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