Localized excitation in the hybridization gap in YbAl3

Abstract

The intermediate valence compound YbAl3 exhibits a broad magnetic excitation with characteristic energy E1 ~ 50meV, of order of the Kondo energy (TK ~ 600-700K). In the low temperature (T < Tcoh ~ 40K) Fermi liquid state, however, a new magnetic excitation arises at E2 ~ 33meV, which lies in the hybridization gap that exists in this compound. We show, using inelastic neutron scattering on a single-crystal sample, that while the scattering at energies near E1 has the momentum (Q-) dependence expected for interband scattering across the indirect gap, the scattering near E2 is independent of Q. This suggests that it arises from a spatially-localized excitation in the hybridization gap.

10 pages plus 4 figures

References in corpus (3)

• Optical conductivity of the Kondo insulator YbB_12: Gap formation and low-energy excitations
• Evidence for short-range antiferromagnetic fluctuations in Kondo-insulating YbB12
• Pseudogap Formation and Heavy Carrier Dynamics in Intermediate Valence YbAl3

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