Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 54: Transport: Carbon Nanotubes

TT 54.5: Vortrag

Mittwoch, 9. März 2016, 16:00–16:15, H22

Emerging Kondo screening and many-body Kramers entanglement in a carbon nanotube — •Michael Niklas¹, Sergey Smirnov¹, Davide Mantelli¹, Magdalena Margańska¹, Jean-Pierre Cleuziou², and Milena Grifoni¹ — ¹Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany — ²Institute Néel, CNRS and Université Grenoble Alpes, BP 166, 38042 Grenoble, France

The entanglement of quantum states is at the heart of the Kondo effect. In its simplest realization, interactions between a localized spin and itinerant electrons give rise to an entangled singlet ground state with no net spin. Carbon nanotubes offer the possibility to study the emergence of this entanglement in a system with orbital and spin degrees of freedom by simply tuning a gate voltage. Here we investigate the magnetospectrum of a carbon nanotube and find the disappearance of some inelastic excitation lines when sweeping the gate voltage from the weak to the strong coupling regime where Kondo behavior is observed. We consider the global SU(2) ⊗ SU(2) symmetry associated to the two Kramers channels of a carbon nanotube and find that only excitations involving flips of the Kramers pseudospins are observed in the Kondo regime, revealing that those pseudospins are fully screened by the conduction electrons.