Spin-one bosons in low-dimensional Mott insulating states

ITP, Utrecht University, Minnaert building - Leuvenlaan 4 3584 CE Utrecht, The Netherlands

Received: 14 April 2003
Accepted: 13 June 2003

Abstract

We analyze the strong-coupling limit of spin-one bosons in low-dimensional lattices. In one-dimensional lattices, for an odd number of bosons per site (), the ground state is a dimerized-valence-bond crystal with a twofold degeneracy; the low-lying elementary spin excitations carry spin-one. For an even number of bosons per site (), the ground state is a nondegenerate spin singlet Mott state. We also argue that for square lattices in a quantum spin disordered limit, ground states should be dimerized-valence-bond crystals for an odd integer N₀. Finally, we briefly report results on exotic states for non-integer numbers of bosons per site in one-dimensional lattices.