Anisotropic spin-dynamics in the Kondo semiconductor CeRu2Al10

TL;DR

This study investigates the anisotropic spin dynamics in the Kondo insulator CeRu2Al10 using neutron scattering, revealing complex excitation behavior and highlighting the importance of hybridization effects.

Contribution

It provides the first detailed neutron scattering analysis of CeRu2Al10's spin dynamics, emphasizing the role of anisotropic hybridization in its magnetic properties.

Findings

Observation of two excitation branches with a gap of 4.8 meV

Dispersion of excitations up to 8.5 meV

Discrepancies between data and RPA magnon calculations

Abstract

Spin dynamics in the new Kondo insulator compound CeRu2Al10 has been studied using unpolarized and polarized neutron scattering on single crystals. In the unconventional ordered phase forming below T0 = 27.3 K, two excitation branches are observed with significant intensities, the lower one of which has a gap of 4.8 +/- 0.3 meV and a pronounced dispersion up to about 8.5 meV. Comparison with RPA magnon calculations assuming crystal-field and anisotropic exchange couplings captures major aspects of the data, but leaves unexplained discrepancies, pointing to a key role of direction-specific hybridization between 4f and conduction band states in this compound.