Disorder-induced excitation continuum in a spin- 12 cobaltate on a triangular lattice

• Published in: Physical review. B 2023-07, Vol.108 (2)
• Main Authors: Gao, Bin, Chen, Tong, Huang, Chien-Lung, Qiu, Yiming, Xu, Guangyong, Liebman, Jesse, Chen, Lebing, Stone, Matthew B., Feng, Erxi, Cao, Huibo, Wang, Xiaoping, Xu, Xianghan, Cheong, Sang-Wook, Winter, Stephen M., Dai, Pengcheng
• Format: Article
• Language: English
• Subjects: antiferromagnets; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; frustrated magnetism; magnetism; quantum spin liquid
• ISSN: 2469-9950
• DOI: 10.1103/PhysRevB.108.024431

A spin-1/2 triangular-lattice antiferromagnet is a prototypical frustrated quantum magnet, which exhibits remarkable quantum many-body effects that arise from the synergy between geometric spin frustration and quantum fluctuations. It can host quantum frustrated magnetic topological phenomena such as quantum spin liquid (QSL) states, highlighted by the presence of fractionalized quasiparticles within a continuum of magnetic excitations. Here, in this work, we use neutron scattering to study CoZnMo3 O8, which has a triangular lattice of Jeff = 1/2 Co2+ ions with octahedral coordination. We found a wave-vector-dependent excitation continuum at low energy that disappears with increasing temperature. Although these excitations are reminiscent of a spin excitation continuum in a QSL state, their presence in CoZnMo3 O8 originates from magnetic intersite disorder-induced dynamic spin states with peculiar excitations. Our results, therefore, provide direct experimental evidence for the presence of a disorder-induced spin excitation continuum.