Modes of magnetic resonance in the spin-liquid phase of Cs2CuCl4

Phys Rev Lett. 2011 Jul 15;107(3):037204. doi: 10.1103/PhysRevLett.107.037204. Epub 2011 Jul 14.

Abstract

We report the observation of a frequency shift and splitting of the electron spin resonance (ESR) mode of the low-dimensional S=1/2 frustrated antiferromagnet Cs2CuCl4 in the spin-correlated state above the ordering temperature 0.62 K. The shift and splitting exhibit strong anisotropy with respect to the direction of the applied magnetic field and do not vanish in a zero field. The low-temperature evolution of the ESR is a result of the modification of the one-dimensional spinon continuum by the uniform Dzyaloshinskii-Moriya interaction within the spin chains.