Ordering Due to Quantum Fluctuations in the Frustrated Heisenberg Model

抄録

The Heisenberg antiferromagnet with both the nearest neighbor and the next nearest neighbor interactions is studied in two and three dimensions. The spin wave excitation spectrum is obtained based on the general four sublattice mean field ground state in the region where the next nearest neighbor interactions prevail. It is shown that the continuous degeneracy of the mean field ground state is lifted by the zero-point spin wave fluctuations and the “strip” state with collinear spin ordering is stabilized.