Figure 64.

(a) The phase diagram of α-RuCl₃ adapted with permission from ref (752). Copyright 2018 Springer Nature. At zero field, the system forms a zigzag magnetic structure as shown in the left inset. For in-plane magnetic field between 7 and 9 T, the system is believed to be in Kitaev QSL state. For fields above 9 T, the system becomes non topological from thermal transport measurements. (b) Wave vector/energy dependence of spin excitation of α-RuCl₃ at 4 and 8 T, adapted with permission under a Creative Commons CC BY 4.0 from ref (753). Copyright 2018 Springer Nature. One can clearly see spin waves stemming from zigzag ordered wave vector (0.5, 0, 0) at 4 T. The scattering centered around Γ points is believed to arise from fractionalized excitations of a Kitaev QSL, which is enhanced upon suppression of spin waves with a 8 T in-plane magnetic field.