Disorder-Induced Excitation Continuum in a Spin-1/2 Cobaltate on a Triangular Lattice

Published

July 31, 2023

Author(s)

Bin Gao, Tong Chen, Chien-Lung Huang, Yiming Qiu, Guangyong Xu, Jesse Liebman, Lebing Chen, Matthew B. Stone, Erxi Feng, Huibo Cao, Xiaoping Wang, Xianghan Xu, Sang-Wook Cheong, Stephen Winter, Pengcheng Dai

Abstract

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 like quantum spin liquid (QSL) states, highlighted by the presence of fractionalized quasiparticles within a continuum of magnetic excitations. In this work, we use neutron scattering to study CoZnMo₃O₈, which has a triangular lattice of J_eff = 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 CoZnMo₃O₈ originates from magnetic intersite disorder induced dynamic spin states with peculiar excitations. Our results therefore give direct experimental evidence for the presence of a disorder-induced spin excitation continuum. We provide a methodology to distinguish these excitations from genuine spin excitation continua from a QSL.

Citation

Physical Review B

Volume

108

Issue

2

Pub Type

Journals

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DOI Link

Keywords

disorder-induced spin excitation continuum, neutron scattering, triangular lattice

Citation

Gao, B. , Chen, T. , Huang, C. , Qiu, Y. , Xu, G. , Liebman, J. , Chen, L. , Stone, M. , Feng, E. , Cao, H. , Wang, X. , Xu, X. , Cheong, S. , Winter, S. and Dai, P. (2023), Disorder-Induced Excitation Continuum in a Spin-1/2 Cobaltate on a Triangular Lattice, Physical Review B, [online], https://dx.doi.org/10.1103/PhysRevB.108.024431 (Accessed April 27, 2024)