Signature of quantum criticality in photoemission spectroscopy at elevated temperature

Abstract

A quantum phase transition (QPT) in a heavy-fermion (HF) compound may destroy the Fermi liquid groundstate. However, the conditions for this breakdown have remained obscure. We report the first direct investigation of heavy quasiparticle formation and breakdown in the canonical system CeCu${}_{6-x}$Au${}_x$ by ultraviolet photoemission spectroscopy at elevated temperatures without the complications of lattice coherence. Surprisingly, the single-ion Kondo energy scale $T_K$ exhibits an abrupt step near the quantum critical Au concentration of $x_c=0.1$. We show theoretically that this step is expected from a highly non-linear renormalization of the local spin coupling at each Ce site, induced by spin fluctuations on neighboring sites. It provides a general high-temperature indicator for HF quasiparticle breakdown at a QPT.

arXiv commentPublished version, PRL, minor changes in wording

References in corpus (10)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Quantum Criticality in Heavy Fermion Metals
• Locally critical quantum phase transitions in strongly correlated metals
• Onset of antiferromagnetism in heavy fermion metals
• How do Fermi liquids get heavy and die?
• Two-dimensional fluctuations at the quantum-critical point of CeCu_{6-x}Au_x
• Spectral Properties of the Anderson Impurity Model, Comparison of Numerical Renormalization Group and Non--Crossing Approximation
• Temperature dependence of the Kondo resonance and its satellites in CeCu_2Si_2
• High Resolution Photoemission Study on Low-T_K Ce Systems: Kondo Resonance, Crystal Field Structures, and their Temperature Dependence
• Structure and transport in multi-orbital Kondo systems

Cited by in corpus (23)

• Heavy Fermions and Quantum Phase Transitions
• Heavy-electron quantum criticality and single-particle spectroscopy
• A Tunable Two-impurity Kondo system in an atomic point contact
• Quantum phase transitions in heavy fermion metals and Kondo insulators
• Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions
• Fermi surface topology of the two-dimensional Kondo lattice model: a dynamical cluster approximation approach
• Microwave spectroscopy on heavy-fermion systems: probing the dynamics of charges and magnetic moments
• Low-Energy Scale Excitations in the Spectral Function of Organic Monolayer Systems
• Kondo Destruction in RKKY-Coupled Kondo Lattice and Multi-Impurity Systems
• Zooming in on heavy fermions in Kondo lattice models
• Nonlocal Kondo effect and quantum critical phase in heavy fermion metals
• Kondo breakdown in a spin-1/2 chain of adatoms on a Dirac semimetal
• Time-resolved collapse and revival of the Kondo state near a quantum phase transition
• Quantum phase transition in a two-dimensional Kondo-Heisenberg model: a Schwinger-boson large-N approach
• Fermi volume evolution and crystal field excitations in heavy-fermion compounds probed by time-domain terahertz spectroscopy
• Evolution of the Kondo resonance feature and its relationship to spin-orbit coupling across the quantum critical point in Ce2Rh{1-x}CoxSi3
• Kondo Breakdown via Fractionalization in a Frustrated Kondo Lattice Model
• Echo of the Quantum Phase Transition of CeCu${}_{6-x}$Au${}_x$ in XPS: Breakdown of Kondo Screening
• Quantum Criticality and Novel Phases: Summary and Outlook
• Kondo screening and beyond: an x-ray absorption and dichroism study of CePt${}_5$/Pt(111)
• High-temperature signatures of quantum criticality in heavy fermion systems
• Missing spectral weight in a heavy-fermion system far above Néel temperature
• Studies of Electronic Structure across a Quantum Phase Transition in CeRhSb${}_{1-x}$Sn${}_x$