High-field magnetic resonance of spinons and magnons in a triangular lattice S=1/2 antiferromagnet Cs2CuCl4

Abstract

The electron spin resonance doublet indicating the width of the two spinon continuum in a spin-1/2 triangular-lattice Heisenberg antiferromagnet Cs2CuCl4 was studied in high magnetic field. The doublet was found to collapse in a magnetic field of a half of the saturation field. The collapse of the doublet occurs via vanishing of the high frequency component in a qualitative agreement with the theoretical prediction for the S=1/2 chain. The field of the collapse is, however, much lower than expected for the S=1/2 chain. This is proposed to be due to the destruction of frustration of interchain exchange bonds in a magnetic field, which restores the 2D character of this spin system. In the saturated phase the mode with the Larmor frequency and a much weaker mode downshifted for 119~GHz are observed. The weak mode is of exchange origin, it demonstrates a positive frequency shift at heating corresponding to the repulsion of magnons in the saturated phase.

7 pages 7 figures

References in corpus (5)

• Unusual ordered phases of highly frustrated magnets: a review
• Spinons and triplons in spatially anisotropic frustrated antiferromagnets
• Spin-orbital effects in magnetized quantum wires and spin chains
• Direct determination of exchange parameters in Cs2CuBr4 and Cs2CuCl4: high-field ESR studies
• Dynamically dominant excitations of string solutions in the spin-1/2 antiferromagnetic Heisenberg chain in magnetic fields

Cited by in corpus (5)

• Evidence for a magnetic field-induced unconventional nematic state in the frustrated and anisotropic spin-chain cuprate LiCuSbO${}_4$
• ESR study of the spin ladder with uniform Dzyaloshinskii-Moria interaction
• Electron spin resonance in a model S=1/2 chain antiferromagnet with a uniform Dzyaloshinskii--Moriya interaction
• Spin gap in a quasi-1D S=1/2 antiferromagnet K2CuSO4Cl2
• Spin relaxation in Cs${}_2$CuCl${}_{4-x}$Br${}_x$