%0 Journal Article
%A Ran, Kejing
%A Wang, Jinghui
%A Bao, Song
%A Cai, Zhengwei
%A Shangguan, Yanyan
%A Ma, Zhen
%A Wang, Wei
%A Dong, Zhao-Yang
%A Cermak, P.
%A Schneidewind, A.
%A Meng, Siqin
%A Lu, Zhilun
%A Yu, Shun-Li
%A Li, Jian-Xin
%A Wen, Jinsheng
%T Evidence for Magnetic Fractional Excitations in a Kitaev Quantum-Spin-Liquid Candidate α-RuCl3
%J Chinese physics letters
%V 39
%@ 0256-307X
%C Bristol
%I IOP Publ.
%M FZJ-2021-06214
%P 027501
%D 2022
%X It is known that 𝛼-RuCl3 has been studied extensively because of its proximity to the Kitaev quantum-spin-liquid(QSL) phase and the possibility of approaching it by tuning the competing interactions. Here we present the firstpolarized inelastic neutron scattering study on 𝛼-RuCl3 single crystals to explore the scattering continuum aroundthe 𝛤 point at the Brillouin zone center, which was hypothesized to be resulting from the Kitaev QSL state butwithout concrete evidence. With polarization analyses, we find that, while the spin-wave excitations around the𝑀 point vanish above the transition temperature 𝑇N, the pure magnetic continuous excitations around the 𝛤point are robust against temperature. Furthermore, by calculating the dynamical spin-spin correlation functionusing the cluster perturbation theory, we derive magnetic dispersion spectra based on the 𝐾–𝛤 model, whichinvolves with a ferromagnetic Kitaev interaction of −7.2meV and an off-diagonal interaction of 5.6 meV. We findthis model can reproduce not only the spin-wave excitation spectra around the 𝑀 point, but also the non-spinwavecontinuous magnetic excitations around the 𝛤 point. These results provide evidence for the existence offractional excitations around the 𝛤 point originating from the Kitaev QSL state, and further support the validityof the 𝐾–𝛤 model as the effective minimal spin model to describe 𝛼-RuCl3.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000752027200001
%R 10.1088/0256-307X/39/2/027501
%U https://juser.fz-juelich.de/record/904645