Coupled S=1/2 Heisenberg antiferromagnetic chains in an effective staggered field -: art. no. 054406

We present a systematic study of coupled S=1/2 Heisenberg antiferromagnetic chains in an effective staggered field. We investigate several effects of the staggered field in the higher (two or three) dimensional spin system analytically. In particular, in the case where the staggered field and the interchain interaction compete with each other, we predict, using mean-field theory, a characteristic phase transition. The spin-wave theory predicts that the behavior of the gaps induced by the staggered field is different between the competitive case and the noncompetitive case. When the interchain interactions are sufficiently weak, we can improve the mean-field phase diagram by using chain mean-field theory and the analytical results of field theories. The ordered phase region predicted by the chain mean-field theory is substantially smaller than that by the mean-field theory.