摘要：The frustrated spin-1/2 J 1-J 2-J 3 antiferromagnet with exchange anisotropy on the two-dimensional square lattice is investigated. The exchange anisotropy is presented by η with 0 ≤ η < 1. The effects of the J 1, J 2, J 3 and anisotropy on the possible phase transition of the Néel state and collinear state are studied comprehensively. Our results indicate that for J 3 > 0 there are upper limits [Formula: see text] and η (c) values. When 0 < J 3 ≤ [Formula: see text] and 0 ≤ η ≤ η (c) , the Néel and collinear states have the same order-disorder transition point at J 2 = J 1/2. Nevertheless, when the J 3 and η values beyond the upper limits, it is a paramagnetic phase at J 2 = J 1/2. For J 3 < 0, in the case of 0 ≤ η < 1, the two states always have the same critical temperature as long as J 2 = J 1/2. Therefore, for J 2 = J 1/2, under such parameters, a first-order phase transition between the two states for these two cases below the critical temperatures may occur. When J 2 ≠ J 1/2, the Néel and collinear states may also exist, while they have different critical temperatures. When J 2 > J 1/2, a first-order phase transition between the two states may also occur. However, for J 2 < J 1/2, the Néel state is always more stable than the collinear state.
