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O: Fachverband Oberflächenphysik

O 88: Electronic Structure: Surface Magnetism and Spin Phenomena

O 88.10: Vortrag

Donnerstag, 19. März 2015, 17:15–17:30, MA 042

State identification and tunable Kondo effect of MnPc — •Andreas Krönlein¹, Jens Kügel¹, Michael Karolak², Pin-Jui Hsu¹, Jacob Senkpiel¹, Giorgio Sangiovanni², and Matthias Bode¹ — ¹Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Germany — ²Institut für Theoretische Physik und Astronomie, Theoretische Physik I, Universität Würzburg, Germany

In the past the Kondo effect of transition metal phthalocyanine (Pc) molecules has been intensively studied [1]. Recently, by combined scanning tunneling spectroscopy (STS) and density functional theory we could show that also MnPc/Ag(001) exhibits a Kondo effect [2]. The STS data could, however, not satisfyingly be fit by a single Fano function. Rather they appear to be a superimposition of the Kondo feature and another, yet unknown contribution. In this presentation we will show that the tunneling spectrum can be fitted by either two Fano functions, which would indicate two separate Kondo channels [3], or by a combination of a Fano and a Gauss function, with the latter representing an orbital state. We find that spatially resolved Kondo maps are only consistent with the second scenario. This is corroborated by a systematic investigation that, in addition to MnPc, also includes FePc and CoPc. In either case progressive dehydrogenation leads to a continuous shift of what is identified as the d_z² molecular orbital. The influence on the Kondo temperature of MnPc will be discussed.
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K.J. Franke et al., Science 332, 6032 (2011).