Inversion Phenomena of the Anisotropies of the Hamiltonian and the Wave-Function in the Distorted Diamond Type Spin Chain
We investigate the ground-sate phase diagram of the XXZ version of the S=1/2 distorted diamond chain by use of the degenerate perturbation theory near the truncation point. In case of the XY-like interaction anisotropy, the phase diagram consists of the Neel phase and the spin-fluid phase. For the Ising-like interaction anisotropy case, it consists of three phases: the ferrimagnetic phase, the Neel phase and the spin-fluid phase. The magnetization in the ferrimagnetic phase is 1/3 of the saturation magnetization. The remarkable nature of the phase diagram is the existence of the Neel phase, although the interaction anisotropy is XY-like. And also, the spin-fluid phase appears in spite of the Ising-like interaction anisotropy. We call these regions "inversion regions".