Site Selective Spontaneous Symmetry Breaking and Partial Order in Kondo Lattices

TL;DR

This paper introduces a new approach combining an effective Hamiltonian and hybrid Monte-Carlo simulations to uncover partially magnetically ordered phases with fractional site screening in Kondo lattices, revealing a site-selective symmetry breaking mechanism.

Contribution

It presents a novel effective Hamiltonian method and hybrid Monte-Carlo simulations to identify and understand partial magnetic order and site-selective symmetry breaking in Kondo lattice models.

Findings

Discovery of PMO phases with fractional Kondo-screened sites (1/4, 3/8, 1/2).

Identification of a non-local ordering mechanism underlying these phases.

Introduction of a site-selective spontaneous symmetry breaking concept.

Abstract

Using the combination of a new effective Hamiltonian approach and hybrid Monte-Carlo simulations, we unveil a variety of partially magnetically ordered (PMO) phases in the Kondo lattice model. Our approximation is motivated by two crucial features of the Hamiltonian: (i) formation of Kondo singlets leading to vanishing local magnetic moments, and (ii) spatially correlated nature of the effective single-particle kinetic energy. We discover PMO phases with fractional values $1/4$, $3/8$, and $1/2$ of Kondo-screened sites. A common understanding of these states emerges in terms of a non-local ordering mechanism. The concept of site-selective spontaneous symmetry breaking introduced here provides a new general approach to study models of interacting fermions in the intermediate coupling regime.