Terahertz Conductivity of Heavy-fermion Systems from Time-resolved Spectroscopy

Abstract

The Drude model describes the free-electron conduction in simple metals, governed by the freedom that the mobile electrons have within the material. In strongly correlated systems, however, a significant deviation of the optical conductivity from the simple metallic Drude behavior is observed. Here, we investigate the optical conductivity of the heavy-fermion system CeCu${}_{6-\mathrm{x}}$Au${}_{\mathrm{x}}$, using time-resolved, phase-sensitive terahertz spectroscopy. Terahertz electric field creates two types of excitations in heavy-fermion materials: First, the intraband excitations that leave the heavy quasiparticles intact. Second, the resonant interband transitions between the heavy and light parts of the hybridized conduction band that break the Kondo singlet. We find that the Kondo-singlet breaking interband transitions do not create a Drude peak, while the Kondo-retaining intraband excitations yield the expected Drude response; thus, making it possible to separate these two fundamentally different correlated contributions to the optical conductivity.

arXiv commentPublished version. $\omega /T$ scaling analysis and appendix added. 12 pages, 10 figures

References in corpus (27)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Quantum Criticality in Heavy Fermion Metals
• Locally critical quantum phase transitions in strongly correlated metals
• Electrodynamics of Correlated Electron Materials
• The break up of heavy electrons at a quantum critical point
• Onset of antiferromagnetism in heavy fermion metals
• How do Fermi liquids get heavy and die?
• Multiple energy scales at a quantum critical point
• Fermi-surface collapse and dynamical scaling near a quantum critical point
• Heavy-electron quantum criticality and single-particle spectroscopy
• Direct observation of how the heavy fermion state develops in CeCoIn5
• Temperature dependence of the Kondo resonance and its satellites in CeCu_2Si_2
• Non-Drude universal scaling laws for the optical response of local Fermi liquids
• High Resolution Photoemission Study on Low-T_K Ce Systems: Kondo Resonance, Crystal Field Structures, and their Temperature Dependence
• Singular charge fluctuations at a magnetic quantum critical point
• Quantum critical properties of the Bose-Fermi Kondo Model in a large-N limit
• Evolution of the Kondo lattice and non-Fermi liquid excitations in a heavy-fermion metal
• Emergent Charge Fluctuations at the Kondo Breakdown of Heavy Fermions
• Kondo volume collapse, Kondo breakdown, and Fermi surface transitions in heavy-fermion metals
• Kondo Destruction in RKKY-Coupled Kondo Lattice and Multi-Impurity Systems
• Microwave conductivity of heavy fermions in UPd2Al3
• Time-resolved collapse and revival of the Kondo state near a quantum phase transition
• Fermi volume evolution and crystal field excitations in heavy-fermion compounds probed by time-domain terahertz spectroscopy
• Pressure-induced residual resistivity anomaly in CeCu_5Au
• Kondo Destruction in Heavy Fermion Quantum Criticality and the Photoemission Spectrum of YbRh${}_2$Si${}_2$
• Electrodynamics of correlated electron systems
• Magnetic order and transport in the heavy-fermion system CeCu_{6-x}Au_x

Cited by in corpus (3)

• Critical slowing down of fermions near a magnetic quantum phase transition
• Missing spectral weight in a heavy-fermion system far above Néel temperature
• Kondo coherence versus superradiance in THz radiation-driven heavy-fermion systems