Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 53: Correlated Electrons: Heavy Fermions
TT 53.13: Talk
Thursday, March 14, 2013, 12:45–13:00, H19
Spin excitons in the unconventional superconducting and hidden order state of strongly correlated electrons — •Alireza Akbari and Peter Thalmeier — Max Planck Institute for the Chemical Physics of Solids, 01187 Dresden, Germany
The formation of collective spin excitons below the single particle continuum is observed in
numerous unconventional superconductors. CeCoIn5 is the most well established case for heavy fermion compounds.
It is also the first example where the magnetic field splitting of magnetic excitons is observed for fields within
the tetragonal plane. Contrary to expectations it is revealed as a doublet excitation. We explain the splitting as the result
of a strongly anisotropic spin response described within the context of an Anderson lattice type model.
Recently it was shown that collective spin excitations also appear within the hidden order phase of non-
superconducting CeB6. It is a signature of the itinerant nature of spin response as opposed to the commonly used
localized 4f approach in this compound. We show that the salient features of the spin exciton can be explained in
an itinerant quasiparticle model supplemented by hidden and antiferromagnetic order.
[1] A. Akbari and P. Thalmeier, Phys. Rev. B 86, 134516 (2012)
A. Akbari and P. Thalmeier, Phys. Rev. Lett. 108, 146403 (2012)