We report an unprecedented quantum criticality crossover representing two different universal scaling behaviors in a Kitaev quantum magnetic material α-RuCl3. α-RuCl3 presents both a symmetry breaking antiferromagnetic order and a long-range entangled topological order of a quantum spin liquid, and thus could be a candidate system for a new universality class involving deconfined fractionalized excitations of the local Z2 fluxes and itinerant Majorana fermions. Theoretical analyses on the inelastic neutron scattering and specific heat results demonstrate that Wilson-Fisher-Yukawa-type 'conventional' weak-coupling quantum criticality in high energy scales crosses over to heavy-fermion-type 'local' strong-coupling one in low energy scales. Our findings provide deep insight on how the quantum criticality evolves in fermion-boson coupled topological systems with different types of deconfined fermions.
@article{arxiv.2203.13407,
title = {Weak-coupling to strong-coupling quantum criticality crossover in a Kitaev quantum spin liquid $\alpha$-RuCl$_3$},
author = {Jae-Ho Han and Seung-Hwan Do and Kwang-Yong Choi and Sang-Youn Park and Jae-You Kim and Sungdae Ji and Ki-Seok Kim and Jae-Hoon Park},
journal= {arXiv preprint arXiv:2203.13407},
year = {2023}
}