We investigate electron spin resonance (ESR) on Cu benzoate, Cu(C 6H5COO)2 · 3H2O, which is an ideal model substance of S = 1/2 antiferromagnetic Heisenberg chain (AFHC) with staggered field. Theoretically, S = 1/2 AFHC subjected to the staggered field exemplifies a good realization of a quantum sine-Gordon (SG) model. In fact, under magnetic fields, this compound develops an energy gap Eg(H) in the low-lying SG excitation spectra as a function of the applied magnetic field H. In the previous work, we observed the SG-breather excitation for the first time, in wide-field range up to 30 T by means of ESR under Faraday configuration. In this work, we report a direct observation of the SG-soliton/antisoliton excitation by ESR under Voigt configuration. Thus, all solutions of the SG equation are now experimentally demonstrated by means of ESR technique.
- Cu benzoate
- Field-induced gap
- Quantum spin
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering