## SciPost Submission Page

# Honeycomb rare-earth magnets with anisotropic exchange interactions

### by Zhu-Xi Luo, Gang Chen

### Submission summary

As Contributors: | Zhu-Xi Luo |

Preprint link: | scipost_202003_00001v6 |

Date submitted: | 2020-05-14 |

Submitted by: | Luo, Zhu-Xi |

Submitted to: | SciPost Physics |

Discipline: | Physics |

Subject area: | Condensed Matter Physics - Theory |

Approach: | Theoretical |

### Abstract

We study the rare-earth magnets on a honeycomb lattice, and are particularly interested in the experimental consequences of the highly anisotropic spin interaction due to the spin-orbit entanglement. We perform a high-temperature series expansion using a generic nearest-neighbor Hamiltonian with anisotropic interactions, and obtain the heat capacity, the parallel and perpendicular spin susceptibilities, and the magnetic torque coefficients. We further examine the electron spin resonance linewidth as an important signature of the anisotropic spin interactions. Due to the small interaction energy scale of the rare-earth moments, it is experimentally feasible to realize the strong-field regime. Therefore, we perform the spin-wave analysis and study the possibility of topological magnons when a strong field is applied to the system. The application and relevance to the rare-earth Kitaev materials are discussed.

###### Current status:

### Author comments upon resubmission

### List of changes

1. Added two sentences below equations (1) and (3) to further explain the setup.

2. Below Eqn (9), added more comments on the magnetometry results.

3. Added another expression for $\Gamma_{ij,zz}$ to equation (12).

4. In the caption of figure 3 and below Eqn (17), added more explanations about the ESR results.

5. Added a reference [45] above Eqn (13) and rephrased the sentences.

6. Added a remark at the beginning of section V about the scale of exchange.

7. Added an estimation of the YbCl3 exchange scales in the second paragraph of the discussion section.

8. Added a remark about high-temperature expansion below equation (B9).

Smaller edits:

9. The second paragraph in the introduction section, changed "proximity" to "relevance".

10. At the beginning of section III, specified that Appendix B contains more details.

11. Below equations (5) and (7), added more explanations of notations.

12. The last paragraph of the last column on page 3, corrected a typo "there is"->"this is".

13. In the caption of figure 2, added more explanations of notations.

14. Below Eqn (11), corrected a typo "a traceless"->"is a traceless".

15. Changed "in" to "along" in the title of section V. B.

16. Corrected a typo "spin-obital" -> "spin-orbital" in the second paragraph of left column on page 7.

17. Added explanation of notation below equation (A1) and (B5).