Ground-state properties of axially anisotropic quantum Heisenberg chains (original) (raw)

The ground state and low-lying excited states of a one-dimensional Heisenberg model with axial anisotropy are studied by extrapolation from finite lattices. The ground-state properties and the phase diagram are determined for quantum spins, especially for S= 2, 1, and 2. Higher spin values do not give new features in the phase diagram. The limitations of finite-lattice extrapolation are discussed in connection with the possibility of a singlet phase for the S=1 isotropic Heisenberg antiferromagnet.