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arXiv · 2203.13407

Weak-coupling to strong-coupling quantum criticality crossover in a Kitaev quantum spin liquid $\alpha$-RuCl$_3$

Jae-Ho Han·Seung-Hwan Do·Kwang-Yong Choi·Sang-Youn Park·Jae-You Kim·Sungdae Ji·Ki-Seok Kim·Jae-Hoon Park
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Abstract

We report an unprecedented quantum criticality crossover representing two different universal scaling behaviors in a Kitaev quantum magnetic material $\alpha$-RuCl$_3$. $\alpha$-RuCl$_3$ 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 Z$_2$ 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.

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Jae-Ho Han, Seung-Hwan Do, Kwang-Yong Choi, Sang-Youn Park, Jae-You Kim, Sungdae Ji, Ki-Seok Kim, Jae-Hoon Park. 2022-03-25. Weak-coupling to strong-coupling quantum criticality crossover in a Kitaev quantum spin liquid $\alpha$-RuCl$_3$. https://doi.org/10.1038/s41535-023-00563-w

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