Orbital Kondo effect in carbon nanotubes

Progress in the fabrication of nanometre-scale electronic devices is opening new opportunities to uncover deeper aspects of the Kondo effect-a characteristic phenomenon in the physics of strongly correlated electrons. Artificial single-impurity Kondo systems have been realized in various nanostructu...

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Bibliographic Details
Published in:Nature 2005-03, Vol.434 (7032), p.484-488
Main Authors: Jarillo-Herrero, Pablo, Kong, Jing, van der Zant, Herre S.J, Dekker, Cees, Kouwenhoven, Leo P, De Franceschi, Silvano
Format: Article
Language:English
Subjects:
Carbon
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems
Electronic conduction in metals and alloys
Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures
Electronic transport in condensed matter
Electrons
Exact sciences and technology
Fabrication
Humanities and Social Sciences
letter
Magnetic fields
Magnetism
multidisciplinary
Nanotechnology
Nanotubes
Physics
Scattering mechanisms and kondo effect
Science
Science (multidisciplinary)
Semiconductors
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Summary:Progress in the fabrication of nanometre-scale electronic devices is opening new opportunities to uncover deeper aspects of the Kondo effect-a characteristic phenomenon in the physics of strongly correlated electrons. Artificial single-impurity Kondo systems have been realized in various nanostructures, including semiconductor quantum dots, carbon nanotubes and individual molecules. The Kondo effect is usually regarded as a spin-related phenomenon, namely the coherent exchange of the spin between a localized state and a Fermi sea of delocalized electrons. In principle, however, the role of the spin could be replaced by other degrees of freedom, such as an orbital quantum number. Here we show that the unique electronic structure of carbon nanotubes enables the observation of a purely orbital Kondo effect. We use a magnetic field to tune spin-polarized states into orbital degeneracy and conclude that the orbital quantum number is conserved during tunnelling. When orbital and spin degeneracies are present simultaneously, we observe a strongly enhanced Kondo effect, with a multiple splitting of the Kondo resonance at finite field and predicted to obey a so-called SU(4) symmetry.
ISSN:0028-0836
1476-4687
DOI:10.1038/nature03422