Spin excitons from hybridized heavy quasiparticles in YbB12 and CeB6
In f-electron compounds the small indirect hybridization gap which is on the scale of the Kondo temperature leads to an enhanced bare spin response around the zone boundary wave vector, Q′ = (π, π, π). Due to the interaction of hybridized quasiparticles a collective spin exciton resonance mode may appear within or at the gap threshold around Q′. It was found in the small hybridization gap semiconductor YbB12 as well as in the heavy fermion metal CeB6. There are similarities to the spin excitons observed within the excitation gap of unconventional superconductors. We use an Anderson lattice type model supplemented by the molecular fields of hidden and magnetic order in the case of CeB6 to calculate the RPA spin response in these compounds. It exhibits the salient feature in frequency and momentum dependence around Q′ found by inelastic neutron scattering.
KeywordsSpin excitons Heavy quasiparticles Hybridization Kondo semiconductor Hidden order
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- G. Friemel, Y. Li, A. Dukhnenko, N. Shitsevalova, N. Sluchanko, A. Ivanov, V. Filipov, B. Keimer and D. Inosov, Nature Communications (2012).Google Scholar