Phys. Rev. B 49, 4352 - 4355 (1994)

Two-magnon light scattering in the layered antiferromagnet NiPS3: Spin-1/2-like anomalies in a spin-1 system

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S. Rosenblum
The Harrison M. Randall Laboratory of Physics, The University of Michigan, Ann Arbor, Michigan 48109-1120

A. H. Francis
Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055

R. Merlin
The Harrison M. Randall Laboratory of Physics, The University of Michigan, Ann Arbor, Michigan 48109-1120

Rapid Communication Received 16 December 1993

Raman spectra of NiPS3 (spin S=1) reveal an anomalously broad two-magnon feature whose relative width is comparable to that shown by La2CuO4 (S=1/2) and other antiferromagnetic copper oxides. The magnetic continuum is strongly coupled to a nearby phonon, whose scattering amplitude interferes with it. These results question the view that the width enhancement in the cuprates stems from large quantum fluctuations intrinsic to S=1/2 systems. It is proposed that the anomaly is due instead to magnon decay involving strong magnetostrictive coupling to phonons.


©1994 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevB.49.4352
DOI: 10.1103/PhysRevB.49.4352
PACS: 75.50.Ee, 75.30.Et, 75.80.+q, 78.30.Hv

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