%0 Journal Article
%T Phase Diagram of $S=1$ Bond-Alternating XXZ chains
%A Atsuhiro Kitazawa
%A Kiyohide Nomura
%A Kiyomi Okamoto
%J Physics
%D 1995
%I arXiv
%R 10.1103/PhysRevLett.76.4038
%X The phase transitions between the XY, the dimer and the Haldane phases of the spin-1 bond-alternating XXZ chain are studied by the numerical diagonalization. We determine the phase diagram at $T=0$ and also identify the universality class with the level spectroscopy. We find that exactly on $\Delta=0$ there is a Berezinskii-Kosterlitz-Thouless transition line which separates the XY and the Haldane phase and there exists a multicritical point of the XY, the dimer and the Haldane phases. We discuss that the critical properties of this model is of the 2-D Ashkin-Teller type reflecting the hidden $Z_2\times Z_2$ symmetry.
%U http://arxiv.org/abs/cond-mat/9511122v1