Kondo quasiparticle dynamics observed by resonant inelastic x-ray scattering

Area of Science:

• Condensed Matter Physics
• Quantum Materials Science
• Materials Chemistry

Background:

• Effective low-energy models, like the Kondo model, have advanced the understanding of quantum materials by explaining phenomena arising from localized and itinerant electron interactions.
• Accurate material-specific models require incorporating crystal field and spin-orbit interactions, posing challenges in understanding how local high-energy electronic degrees of freedom contribute to collective states.

Purpose of the Study:

• To investigate the role of local high-energy electronic degrees of freedom in correlated metals.
• To clarify the behavior of all relevant energy scales in quantum materials, specifically focusing on hybridization effects.

Main Methods:

• Utilized resonant inelastic x-ray scattering (RIXS) to probe electronic excitations in CePd₃.
• Analyzed the momentum-dependence of spin-orbit excited states at low temperatures.

Main Results:

• Observed that spin-orbit excited states exhibit significant momentum-dependence at low temperatures.
• This momentum-dependence indicates hybridization between localized electronic degrees of freedom and the underlying metallic state.

Conclusions:

• Demonstrated that localized electronic degrees of freedom impart novel properties to correlated metals.
• This finding is critical for a microscopic understanding of emergent phenomena in quantum materials, including superconductivity, electronic nematicity, and topological states.