Anisotropic spin dynamics in the Kondo semiconductor CeRu2Al10

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Kondo insulators are a class of materials exhibiting unique electronic properties due to the interaction between localized f-electrons and conduction band electrons.
• Understanding the spin dynamics in these materials is crucial for exploring their potential applications in quantum technologies.

Purpose of the Study:

• To investigate the spin dynamics and magnetic excitations in the newly discovered Kondo insulator compound, Cerium Ruthenium Aluminum (CeRu2Al10).
• To elucidate the nature of the unconventional ordered phase and the underlying interactions governing its magnetic behavior.

Main Methods:

• Utilized unpolarized and polarized neutron scattering techniques on single crystals of CeRu2Al10.
• Performed random-phase approximation (RPA) magnon calculations incorporating crystal-field and anisotropic exchange couplings.

Main Results:

• Observed two distinct excitation branches with significant intensities in the ordered phase below T0 = 27.3 K.
• Identified a lower excitation branch with a gap of 4.8 ± 0.3 meV and pronounced dispersion up to approximately 8.5 meV.
• RPA calculations partially reproduced the experimental data but highlighted discrepancies.

Conclusions:

• The observed spin dynamics suggest an unconventional ordered phase in CeRu2Al10.
• Discrepancies between experimental data and theoretical calculations point to the significant role of direction-specific hybridization between 4f and conduction band states.
• Further theoretical and experimental investigations are needed to fully understand the electronic structure and magnetic interactions in this material.