On the phase structure of spin-1 planar magnetic chains

The phase structure of a class of quantum spin-1 chains with axial symmetry is analyzed in the light of a pseudospin approach developed recently for the study of planar ferromagnets. The prominent feature of the resulting picture is that a transition to a Goldstone-like phase occurs at some critical coupling, in spite of the one-dimensional nature of the system which would prevent spontaneous breaking of the axial symmetry in the ordinary sense.