Zero Temperature Phases of the Frustrated J 1-J 2 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 N,el 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.