Weak-coupling to strong-coupling quantum criticality crossover in a Kitaev quantum spin liquid α-RuCl3

We report an unprecedented quantum criticality crossover representing two different universal scaling behaviors in a Kitaev magnetic material $\alpha$-RuCl$_3$. $\alpha$-RuCl$_3$ presents both symmetry breaking antiferromagnetic order and long-range entangled topological of spin liquid, thus could be candidate system for new universality class involving deconfined fractionalized excitations the local Z$_2$ fluxes itinerant Majorana fermions. Theoretical analyses on inelastic neutron scattering specific heat results demonstrate that Wilson-Fisher-Yukawa-type 'conventional' weak-coupling high energy scales crosses over to heavy-fermion-type 'local' strong-coupling one low scales. Our findings provide deep insight how evolves fermion-boson coupled systems with types