Critical Properties of Spectral Functions for the 1D Anisotropict-JModels with an Energy Gap
Tatsuya Fujii, Yasumasa Tsukamoto, Norio Kawakami
We exactly calculate the momentum-dependent critical exponents for spectral functions in the one-dimensional anisotropic t-J models with a gap either in the spin or charge excitation spectrum. Our approach is based on the Bethe ansatz technique combined with finite-size scaling techniques in conformal field theory. It is found that the spectral functions show a power-law singularity, which occurs at frequencies determined by the dispersion of a massive spin (or charge) excitation.We discuss how the nontrivial contribution of a massive excitation controls the singular behavior in optical response functions.
arXiv:cond-mat/9710237•Journal of the Physical Society of Japan•Sep 15, 1997•5 citations