Magnetization cusp singularities of frustrated Kondo necklace model

TL;DR

This paper investigates magnetization cusp singularities in a frustrated Kondo necklace model using DMRG and band theory, revealing low-magnetization cusps due to frustration effects and analyzing their critical behaviors.

Contribution

It introduces a combined DMRG and band theory approach to explain low-magnetization cusp singularities caused by frustration in the Kondo necklace model.

Findings

Cusp singularities appear in both low and high magnetization regions.

Low-magnetization cusp is linked to a double-well band structure from frustration.

Phase diagram indicates conditions for cusp occurrence.

Abstract

Magnetization processes of frustrated Kondo necklace model are studied by means of a density matrix renormalization group (DMRG) method and an elementary band theory based on a bond-operator formalism. The DMRG calculations clearly show the cusp singularity in a low-magnetization region ($0<m<1/2$) besides that in a high-magnetization region ($1/2<m<1$) which is expected from previous studies on the magnetization curve of the Majumdar-Ghosh model. An appearance mechanism of the low-magnetization cusp is interpreted in terms of a double-well shape of a low-energy band arising from frustrations between nearest- and next-nearest-neighbor interactions. We also discuss critical behaviors of magnetization near the cusp and obtain a phase diagram showing whether the cusp appears in the magnetization curve or not.