Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 111: Correlated Electrons: Quantum Impurities, Kondo Physics

TT 111.2: Vortrag

Freitag, 20. März 2015, 09:45–10:00, H 3005

Kondo temperature in the Anderson-Holstein Model with a displacement dependent hybridization. — •Andre Jovchev and Frithjof B. Anders — Technische Universität Dortmund, Lehrstuhl für Theoretische Physik II, 44221 Dortmund

Molecular junctions are potential candidates for future nano-electronic devices since they exhibit interesting phenomena such as nonlinear I-V curves and hysteresis effects attributed to conformational change in the molecule. Since the tunnel coupling depends exponentially on the distance, we have studied the influence of the vibrational couplings on the Kondo temperature in the Anderson-Holstein model(AHM) with a modified hybridisation term using the numerical renormalisation group (NRG). This includes a minimal model for the coupling of molecular vibrational modes to the electronic degree of freedom augmented with a vibrational dependent tunnelling term. Our investigation has been motivated by scanning tunnelling microscope experiments where the Kondo temperature in Co and Cu complexes on metallic surfaces has been reported to be mainly independent of the applied gate voltage which is in disagreement with the standard theory of the spin 1/2 Kondo effect.