Zero Temperature Phases of the Frustrated J1–J2 Antiferromagnetic Spin-1/2 Heisenberg Model on a Simple Cubic Lattice

At zero temperature magnetic phases of the quantum spin-1/2 Heisenberg antiferromagnet on a simple cubic lattice with competing first and second neighbor exchanges ( J 1 and J 2 ) is investigated using the non-linear spin wave theory. We find existence of two phases: a two sublattice Néel phase for small J 2 (AF), and a collinear antiferromagnetic phase at large J 2 (CAF). We obtain the sublattice magnetizations and ground state energies for the two phases and find that there exists a first order phase transition from the AF-phase to the CAF-phase at the critical transition point, p c =0.56 or J 2 / J 1 =0.28. We also show that the quartic 1/ S corrections due spin-wave interactions enhance the sublattice magnetization in both the phases which causes the intermediate paramagnetic phase predicted from linear spin wave theory to disappear.