Signature of Kondo breakdown quantum criticality in optical conductivity

Abstract

We study the finite-frequency inter-band transition peak in the optical conductivity of a heavy fermion system close to a Kondo breakdown quantum critical point, where the lattice Kondo temperature vanishes. As the system approaches the phase transition from the heavy Fermi liquid side, we find a new cross-over regime where the peak position is related to, but is not directly proportional to, the lattice Kondo scale. In particular, the position of the peak moves to lower energies, but remains finite at the critical point. On the other hand, the peak value changes non-monotonically and eventually the peak disappears at the quantum critical point, indicating the decoupling of the narrow band of f-electrons from the conduction band. We argue that these are unique signatures of a Kondo breakdown transition, and therefore can be useful to distinguish it experimentally from a spin density wave instability.

4 pages, 3 figures

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Cited by in corpus (5)

• Quantum Criticality and Global Phase Diagram of Magnetic Heavy Fermions
• Orbital-selective Mott transitions: Heavy fermions and beyond
• The thermopower as a signature of quantum criticality in heavy fermions
• Alternative Kondo breakdown mechanism: Orbital-selective orthogonal metal transition
• Emergence of heavy quasiparticles from a massless Fermi sea: Optical conductivity