Ground-state phase diagram of the $S = 1$ one-dimensional Kondo lattice model with a uniaxial anisotropy under transverse fields

TL;DR

This study explores the phase diagram of the one-dimensional $S=1$ Kondo lattice model with uniaxial anisotropy under transverse magnetic fields, revealing diverse magnetic phases and phenomena like the Kondo plateau and metamagnetism.

Contribution

It provides a detailed analysis of the phase diagram and magnetic properties of the $S=1$ Kondo lattice model under transverse fields, incorporating effects relevant to URhGe.

Findings

Identification of ferromagnetic, antiferromagnetic, and Kondo plateau phases.

Observation of pseudoplateau in magnetization due to bound electron pairs.

Detection of metamagnetic behavior at phase boundaries.

Abstract

We study the effects of transverse magnetic fields on the $S=1$ one-dimensional Kondo lattice model with a uniaxial anisotropy using the density matrix renormalization group. The model can be regarded as a simplified one for analyzing the Ising ferromagnetic superconductor URhGe. We find various phases such as ferromagnetic and antiferromagnetic phases, Kondo plateau (KP) phases, Tomonaga-Luttinger liquids, and fully polarized phases. In the KP phase, a pseudoplateau emerges in the magnetization due to strongly bound pairs between the local and the conduction electron spins. This is why we call this phase the Kondo plateau. At the critical field between the ferromagnetic and KP phases, we find metamagnetic behavior in the magnetization curve. We discuss various correlation functions and the Friedel oscillations in detail, and the experimental data under transverse magnetic fields in URhGe are discussed on the basis of the present results.