Emergence of the isotropic Kitaev honeycomb lattice <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>α</mml:mi> <mml:mo>−</mml:mo> </mml:math> RuCl<sub>3</sub> and its magnetic properties
Sang‐Youn Park, Seung-Hwan Do, Kwang‐Yong Choi, Dong‐Jin Jang, Tae-Hwan Jang, John R. Scheffer, Chun-Ming Wu, J. S. Gardner, J. M. Sungil Park, Jae‐Hoon Park, Sungdae Ji
Abstract
using 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.