The spatially anisotropic triangular antiferromagnet is investigated with the numerical diagonalization method. As the anisotropy varies, the model changes into a variety of systems such as the one-dimensional, triangular, and square-lattice antiferromagnets. Taking into account such a geometrical character, we impose the screw-boundary condition, which interpolates smoothly the one- and two-dimensional lattice structures. Diagonalizing the finite clusters with N=16,20,...,32 spins, we observe an intermediate phase between the valence-bond solid (VBS) and Néel phases. Suppressing the intermediate phase by applying the ring exchange, we realize a direct VBS-Néel transition. The simulation data indicate that the transition is a continuous one with the correlation-length critical exponent ν=0.80 (15). These features are in agreement with the deconfinement-criticality scenario advocated by Senthil and co-workers in the context of the high-temperature superconductivity.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Feb 20 2009|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics