Rocha-Filho, G. M.; Pires, A. S.T.; Gouvêa, M. E. - In: The European Physical Journal B - Condensed Matter and … 56 (2007) 1, pp. 7-14
We study the one-dimensional isotropic spin-1 Heisenberg magnet with antiferromagnetic nearest-neighbor (nn) and next-nearest-neighbor (nnn) interactions by using the modified spin wave theory (MSWT). The ground state energy and the singlet-triplet energy gap are obtained for several values of...
