【Topical Review】香港大学陈钢老师研究组：自旋-1焦绿石反铁磁体: 理论、模型与材料评述

Original Front. Phys. 蔻享学术 2021-04-26

TOPICAL REVIEW

Yong-Hao Gao, Xu-Ping Yao, Fei-Ye Li, and Gang Chen, Spin-1 pyrochlore antiferromagnets: Theory, model, and materials’ survey, Front. Phys. 15(6), 63201 (2020)

文章信息

Pyrochlore magnets can be a unique platform to demonstrate numerous important concepts and applications of frustrated magnetic physics in modern condensed matter physics. Most works on pyrochloremagnets deal with the interacting spin-1/2 local moments, while much less works have studied thespin-1 systems. We here review the physics with interacting spin-1 local moments on the pyrochlorelattice to illustrate the potentially interesting physics associated with spin-1 magnets. The genericpyrochlore spin-1 model includes the antiferromagnetic Heisenberg interaction, the Dzyaloshinskii–Moriya interaction and the single-ion spin anisotropy. The global phase diagram of this generic spinmodel is reviewed, and the relation between different quantum phases in the phase diagram is clarified. The critical properties of the transition from the parent quantum paramagnet to the proximateorders are discussed. The presence of quantum order by disorder in the parts of the ordered phases isanalyzed. The elementary excitations with respect to the ground states are further reviewed, and thetopological natures of these excitations are carefully addressed. The materials’ relevance of the spin-1pyrochlore magnets are finally reviewed. This review may provide insights about the interesting spin-1local moments on frustrated systems.

Keywords topological magnon, quantum order by disorder, Dzyaloshinskii–Moriya interaction, flavorwave theory

contents

1 Introduction

2 Model Hamiltonian

3 Flavor wave theory for quantum paramagnet

3.1 Flavor wave representation

3.2 Ideas of linear flavor wave theory

3.3 Critical properties from flavor wave theory

4 Mean-field theory

4.1 All-in all-out AFM

4.2 Splayed FM

4.3 Coplanar XY AFM₁