Coexistence of random singlets and disordered Kitaev spin liquid in H3LiIr2O6

Abstract

©2023 American Physical Society. We combine static magnetic susceptibility chi(T), muon-spin relaxation, and H-1 nuclear magnetic resonance measurements to explore the spin dynamics in the disordered-induced quantum spin liquid candidate H3LiIr2O6. Inverse Laplace transform analysis of the H-1 spin-lattice relaxation rate 1/T-1 enables us to identify two characteristic temperatures Tg = 110 K and T* = 26 K. Below T-g, a slower 1/T-1(slow) component dictated by gapped excitations with a spin gap Delta(h) = 30-38 K evolves distinctly from a faster 1/T-1(fast) component pertaining to gapless excitations. Furthermore, we observe a sub-Curie divergent chi(T) proportional to T-0.68, a power-law dependent 1/T fast 1 proportional to T 1.4, and a weakly activated 1/(slow)(T) 1 proportional to exp(-Delta(l)/k(B)T) (Delta(l) = 3-6 K) below T* = 26 K. All these features suggest the coexistence of a disordered spin-liquid state and spin singlets with spatially distributed gaps.