Bound Spinons in an Antiferromagnetic S=1/2 Chain with a Staggered Field
Abstract
Inelastic neutron scattering was used to measure the magnetic field dependence of spin excitations in the antiferromagnetic S=1/2 chain CuCl2·2(dimethylsulfoxide) in the presence of uniform and staggered fields. Dispersive bound states emerge from a zero-field two-spinon continuum with different finite energy minima at wave numbers q=π and qi≈π(1-2<Sz>). The ratios of the field dependent excitation energies are in excellent agreement with predictions for breather and soliton solutions to the quantum sine-Gordon model, the proposed low-energy theory for S=1/2 chains in a staggered field. The data are also consistent with the predicted soliton and n=1,2 breather polarizations and scattering cross sections.
- Publication:
-
Physical Review Letters
- Pub Date:
- July 2004
- DOI:
- 10.1103/PhysRevLett.93.017204
- arXiv:
- arXiv:cond-mat/0305476
- Bibcode:
- 2004PhRvL..93a7204K
- Keywords:
-
- 75.25.+z;
- 75.10.Jm;
- 75.40.Gb;
- Spin arrangements in magnetically ordered materials;
- Quantized spin models;
- Dynamic properties;
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Statistical Mechanics
- E-Print:
- 4 pages RevTex4, resubmitted to PRL