A fractional-spin phase in the power-law Kondo model

  • M. Vojta
  • R. Bulla

Abstract:

We consider a Kondo impurity coupled to a fermionic host with a power-law density of states near the Fermi level, ρ(ε) ∼ |ε|r, with exponent r < 0. Using both perturbative renormalization group (poor man's scaling) and numerical renormalization group methods, we analyze the phase diagram of this model for ferromagnetic and antiferromagnetic Kondo coupling. Both sectors display non-trivial behavior with several stable phases separated by continuous transitions. In particular, on the ferromagnetic side there is a stable intermediate-coupling fixed point with universal properties corresponding to a fractional ground-state spin.

PACS. 75.20.Hr Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions – 71.10.Hf Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems 

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Copyright information

© EDP Sciences, Springer-Verlag 2002

Authors and Affiliations

  • M. Vojta
    • 1
  • R. Bulla
    • 1
  1. 1.Theoretische Physik III, Elektronische Korrelationen und Magnetismus, Universität Augsburg, 86135 Augsburg, GermanyDE

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