Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 73: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles V (jointly with TT)

O 73.8: Talk

Thursday, March 29, 2012, 18:00–18:15, HE 101

Full ab initio theory of the Kondo effect in molecular devices — •David Jacob — MPI für Mikrostrukturphysik Halle

When a magnetic molecule is deposited on a metallic substrate or attached to metallic contacts its magnetic moment can actually be screened by the conduction electrons due to the Kondo effect. In view of possible applications of magnetic molecules for nanoscale spintronics and magnetic storage devices, it is important to reliably predict whether the Kondo effect will take place or not in a given system, and how it can be controlled by various parameters. From a more fundamental point of view, magnetic molecules in contrast to bulk systems offer the possibility to study exotic variants of the Kondo effect such as the orbital Kondo effect [1] or the underscreened Kondo effect [2]. Here we present a full ab initio method for molecular devices that combines the COHSEX approximation with more sophisticated many-body techniques like the One-Crossing-Approximation for treating the strong correlations of localized electrons that give rise to the Kondo effect. This method is a further development of our previous method [3,4] that was not yet fully ab initio due its dependence on the interaction between the localized electrons as a parameter. The application of our method to various magnetic molecules attached to metallic leads or deposited on surfaces sheds light on the complex nature of the Kondo effect in molecular-scale devices. [1] M. Karolak et al., PRL 107, 146604 (2011); [2] J. J. Parks et al., Science 328, 1370 (2010); [3] D. Jacob et al., PRL 103, 016803 (2009); [4] D. Jacob et al., PRB 82, 195115 (2010)