Magnetic-Field Probing of an SU(4) Kondo Resonance in a Single-Atom Transistor

G. C. Tettamanzi, J. Verduijn, G. P. Lansbergen, M. Blaauboer, M. J. Calderón, R. Aguado, and S. Rogge
Phys. Rev. Lett. 108, 046803 – Published 25 January 2012
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Abstract

Semiconductor devices have been scaled to the point that transport can be dominated by only a single dopant atom. As a result, in a Si fin-type field effect transistor Kondo physics can govern transport when one electron is bound to the single dopant. Orbital (valley) degrees of freedom, apart from the standard spin, strongly modify the Kondo effect in such systems. Owing to the small size and the s-like orbital symmetry of the ground state of the dopant, these orbital degrees of freedom do not couple to external magnetic fields which allows us to tune the symmetry of the Kondo effect. Here we study this tunable Kondo effect and demonstrate experimentally a symmetry crossover from an SU(4) ground state to a pure orbital SU(2) ground state as a function of magnetic field. Our claim is supported by theoretical calculations that unambiguously show that the SU(2) symmetric case corresponds to a pure valley Kondo effect of fully polarized electrons.

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  • Received 15 February 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.046803

© 2012 American Physical Society

Authors & Affiliations

G. C. Tettamanzi1,2,*, J. Verduijn1,2, G. P. Lansbergen1, M. Blaauboer1, M. J. Calderón3, R. Aguado3, and S. Rogge1,2

  • 1Delft University of Technology, Kavli Institute of Nanoscience, Department of Quantum Nanoscience, Lorentzweg 1, 2628 CJ Delft, The Netherlands
  • 2Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
  • 3Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC Cantoblanco, E-28049 Madrid, Spain

  • *g.tettamanzi@unsw.edu.au

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Issue

Vol. 108, Iss. 4 — 27 January 2012

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