The fate of Kondo resonances in certain Kondo lattices: a ``poor woman's'' scaling analysis

TL;DR

This paper develops an effective field theory for Kondo lattices, revealing a non-Fermi liquid phase near an antiferromagnetic transition, with a phase diagram derived from RG analysis showing different magnetic and electronic phases.

Contribution

It introduces a novel bosonic Kondo-Heisenberg model with Grassmann fields and provides a one-loop RG analysis to map the phase diagram of Kondo lattices.

Findings

Identification of a non-Fermi liquid phase near the AF transition

Phase diagram showing AF order, heavy electron phase, and breakdown of Fermi liquid theory

Effective field theory approach for Kondo lattice behavior

Abstract

We present an effective field theory for the Kondo lattice, which can exhibit, in a certain range of parameters, a non Fermi liquid paramagnetic phase at the brink of a zero temperature Anti Ferromagnetic (AF) transition. The model is derived in a natural way from the bosonic Kondo-Heisenberg model, in which the Kondo resonances are treated as true (but damped) Grassmann fields. One loop Renormalization Group (RG) treatment of this model gives a phase diagram for the Kondo lattice as a function of $ J_K $ where, for $ J_K< J_c$ the system shows AF order, for $J_K> J_1$ one has the heavy electron phase and for $ J_c < J_K < J_1$ the formation of the Kondo singlets is incomplete, leading to the breakdown of the Landau Fermi liquid theory.