STRONGLY DISORDERED ANTIFERROMAGNETIC SPIN-1 CHAINS WITH RANDOM ANISOTROPY

The zero-temperature phase diagram of the anisotropic, strongly disord ered antiferromagnetic quantum spin-1 chain is investigated, within th e framework of a real-space renormalization-group approach. In the pre sence of uniform anisotropy there occurs a phase transition from a ran dom singlet phase to an Ising antiferromagnetic phase controlled by a fixed point that does not have Heisenberg symmetry. We find evidence o f a fixed point due to randomness in the anisotropy similar to that wh ich occurs for quantum Heisenberg spin-1 chains.[S0163-1829(98)01626-9 ].