Two-fluid behavior of the Kondo lattice in the 1/N slave boson approach

TL;DR

This paper uses a 1/N slave boson approach to analyze the two-fluid behavior in Kondo lattices, confirming the coexistence of impurity and heavy electron contributions below the coherence temperature.

Contribution

It provides a theoretical demonstration that the two-fluid model arises naturally from the 1/N slave boson treatment of the periodic Anderson model.

Findings

Two contributions emerge below the coherence temperature: Kondo impurity and heavy electron Fermi liquid.

Kondo impurity contribution corresponds to thermal excitations into the flat energy spectrum.

The analysis supports the phenomenological two-fluid model observed experimentally.

Abstract

It has been recently shown by Nakatsuji, Pines, and Fisk [S. Nakatsuji, D. Pines, and Z. Fisk, Phys. Rev. Lett. 92, 016401 (2004)] from the phenomenological analysis of experiments in Ce1-xLaxCoIn5 and CeIrIn5 that thermodynamic and transport properties of Kondo lattices below coherence temperature can be very successfully described in terms of a two-fluid model, with Kondo impurity and heavy electron Fermi liquid contributions. We analyze thermodynamic properties of Kondo lattices using 1/N slave boson treatment of the periodic Anderson model and show that these two contributions indeed arise below the coherence temperature. We find that the Kondo impurity contribution to thermodynamics corresponds to thermal excitations into the flat portion of the energy spectrum.