https://doi.org/10.1140/epjb/e2002-00231-9
A fractional-spin phase in the power-law Kondo model
Theoretische Physik III, Elektronische Korrelationen und
Magnetismus, Universität Augsburg, 86135 Augsburg, Germany
Corresponding author: a matthias.vojta@physik.uni-augsburg.de
Received:
18
February
2002
Published online:
31
July
2002
We consider a Kondo impurity coupled to a fermionic host
with a power-law density of states near the Fermi level,
, 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
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002
