Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 45: Correlated Electrons: Poster Session
TT 45.9: Poster
Donnerstag, 29. März 2012, 15:00–19:00, Poster B
Theory of the Spin Exciton Formation inside the Hidden Order Phase of CeB6 — •Alireza Akbari and Peter Thalmeier — Max Planck Institute for the Chemical Physics of Solids, D-01187 Dresden, Germany
The heavy fermion metal CeB 6 exhibits hidden order of antiferroquadrupolar (AFQ) type below TQ=3.2K
and subsequent antiferromagnetic (AFM) order at TN=2.3K.
It was interpreted as ordering of the quadrupole and dipole moments of a Γ8 quartet of localised Ce 4f1 electrons.
This established picture has been profoundly shaken by recent inelastic neutron scattering [1] that found the
evolution of a feedback spin exciton resonance within the hidden order phase at the AFQ wave vector appears and is
stabilized by the AFM order. We develop an alternative theory based on a fourfold degenerate Anderson lattice model,
including both order parameters as particle-hole condensates of itinerant heavy quasiparticles.
This explains in a natural way the appearance of the spin exciton resonance and the momentum
dependence of its spectral weight, in particular around the AFQ vector and its rapid disappearance
in the disordered phase. Analogies to the feedback effect in unconventional superconductors and
Kondo semiconductors are pointed out.
G. Friemel et al., arXiv:1111.4151.