Botet and Jullien [Phys. Rev. B 27, 613 (1983)] have conducted a finite-chain scaling analysis on the spin-1 antiferromagnetic Heisenberg-Ising chain. They claim that the ground-state properties are completely different from the case of spin
21. Using finite-size scaling techniques, they conclude that between the
XY gapless phase and the doublet-ground-state N\'eel phase, a new phase appears in an extended anisotropy range. This phase, which encompasses the isotropic Heisenberg model, is characterized by a nonmagnetic singlet ground state and a nonzero excitation-energy gap. We perform a similar finite-chain scaling analysis on the spin-
21 antiferromagnetic Heisenberg-Ising chain and obtain strikingly similar results. Since the spin-
41 system is known rigorously not to exhibit the type of behavior proposed by Botet and Jullien, their analysis is open to doubt. The possibility arises that a strong singularity at the Heisenberg point for spin 1 (similar to the essential singularity for spin
21) may be giving rise to misleading results. The
T=0 phase behavior of the spin-1 Heisenberg-Ising antiferromagnetic chain, therefore, remains in question and specific additional numerical studies are proposed to clarify the matter.
work' which also agrees very well with field theory pre- dictions once logarithmic corrections are taken into account. Our statement summarizing previous numerical work pertinentto critical behavior at the Bethe-Ansatz- solvable point was not correct.Critical exponents at this point, along with the possibility of logarithmic correc- tions, had been studied previously by Blote, Bonner, and co-workers, ' and, more recently, by Alcaraz and Martins.We are grateful to J. C. Bonner for bringing this to our attention.We have also discovered that, due to a coding error, the expansions in the dimerization parameter X for an- isotropy h, W1 were incorrect.The estimated critical points are only affected significantly for A& 1: The point C in Fig. 1 should be moved from k =0 to