Emergence of the isotropic Kitaev honeycomb latticeα-RuCl3and its magnetic properties

Sang-Youn Park; Seung-Hwan Do; Kwang-Yong Choi; D Jang; Tae-Hwan Jang; J Scheffer; Chun-Ming Wu; J S Gardner; J M S Park; Jae-Hoon Park; Sungdae Ji

doi:10.1088/1361-648X/ad294f

Emergence of the isotropic Kitaev honeycomb latticeα-RuCl₃and its magnetic properties

J Phys Condens Matter. 2024 Feb 27;36(21). doi: 10.1088/1361-648X/ad294f.

Authors

Sang-Youn Park^{1

2}, Seung-Hwan Do^{1

3}, Kwang-Yong Choi⁴, D Jang⁵, Tae-Hwan Jang¹, J Scheffer⁶, Chun-Ming Wu⁷, J S Gardner^{8

9}, J M S Park¹⁰, Jae-Hoon Park^{1

11

12}, Sungdae Ji¹⁰

Affiliations

¹ Max Planck POSTECH/Korea Research Initiative, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.
² Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea.
³ Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, United States of America.
⁴ Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea.
⁵ Center for Thermometry and Fluid Flow Metrology, Division of Physical Metrology, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea.
⁶ Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institut, Villigen PSI CH-5232, Switzerland.
⁷ National Synchrotron Radiation Research Center, Hsinchu 300092, Taiwan.
⁸ Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America.
⁹ Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia.
¹⁰ Advanced Quantum Materials Research Section, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea.
¹¹ Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.
¹² Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.

PMID: 38354419
DOI: 10.1088/1361-648X/ad294f

Abstract

We present a comprehensive investigation of the crystal and magnetic structures of the van der Waals antiferromagnetα-RuCl₃using single crystal x-ray and neutron diffraction. The crystal structure at room temperature is a monoclinic (C2/m). However, with decreasing temperature, a remarkable first-order structural phase transition is observed, leading to the emergence of a rhombohedral (R3-) structure characterized by three-fold rotational symmetry forming an isotropic honeycomb lattice. On further cooling, a zigzag-type antiferromagnetic order develops belowTN=6∼6.6K. The critical exponent of the magnetic order parameter was determined to beβ=0.11(1), which is close to the two-dimensional Ising model. Additionally, the angular dependence of the magnetic critical field of the zigzag antiferromagnetic order for the polarized ferromagnetic phase reveals a six-fold rotational symmetry within theab-plane. These findingsreflect the symmetry associated with the Ising-like bond-dependent Kitaev spin interactions and underscore the universality of the Kitaev interaction-dominated antiferromagnetic system.

Keywords: Kitaev spin model; neutron diffraction; quantum magnetism.