Phase diagram of the one-dimensional, two-channel Kondo lattice model

TL;DR

This paper maps the phase diagram of a one-dimensional two-channel Kondo lattice model, revealing different magnetic phases and a quantum critical point using numerical and analytical methods.

Contribution

It provides the first detailed phase diagram of the 1D two-channel Kondo lattice model at various fillings and coupling strengths.

Findings

Weak-coupling phase dominated by RKKY exchange

Strong-coupling phase with antiferromagnetic channel correlations

Existence of a quantum critical point separating phases

Abstract

Employing the density matrix renormalization group method and strong-coupling perturbation theory, we study the phase diagram of the SU(2)xSU(2) Kondo lattice model in one dimension. We show that, at quarter filling, the system can exist in two phases depending on the coupling strength. The weak-coupling phase is dominated by RKKY exchange correlations while the strong-coupling phase is characterized by strong antiferromagnetic correlations of the channel degree of freedom. These two phases are separated by a quantum critical point. For conduction-band fillings of less than one quarter, we find a paramagnetic metallic phase at weak coupling and a ferromagnetic phase at moderate to strong coupling.