The quantum J1-J1′-J2 spin-1/2 Heisenberg model: Influence of the interchain coupling on the ground-state magnetic ordering in two dimensions

Abstract

We study the phase diagram of the two-dimensional (2D) J1-J 1′-J2 spin-1/2 Heisenberg model by means of the coupled cluster method. The effect of the coupling J1′ on the Néel and stripe states is investigated. We find that the quantum critical points for the Néel and stripe phases increase as the coupling strength J1′ is increased, and an intermediate phase emerges above the region at J1′≈0.6 when J1 = 1. We find indications for a quantum triple point at J1′≈0.60 0.03, J2≈0.33 0.02 for J1 = 1. © 2008 IOP Publishing Ltd.