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Localized excitation in the hybridization gap in YbAl3

A. D. Christianson·J. M. Lawrence·E. A. Goremychkin·R. Osborn·E. D. Bauer·J. L. Sarrao·J. D. Thompson·C. D. Frost·J. L. Zarestky
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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.

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A. D. Christianson, J. M. Lawrence, E. A. Goremychkin, R. Osborn, E. D. Bauer, J. L. Sarrao, J. D. Thompson, C. D. Frost, J. L. Zarestky. 2005-10-25. Localized excitation in the hybridization gap in YbAl3. https://doi.org/10.1103/physrevlett.96.117206

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