Frustrated quantum Heisenberg ferrimagnetic chains
Abstract
We study the ground-state properties of weakly frustrated Heisenberg ferrimagnetic chains with nearest and next-nearest neighbor antiferromagnetic exchange interactions and two types of alternating sublattice spins S_1 > S_2, using 1/S spin-wave expansions, density-matrix renormalization group, and exact- diagonalization techniques. It is argued that the zero-point spin fluctuations completely destroy the classical commensurate- incommensurate continuous transition. Instead, the long-range ferrimagnetic state disappears through a discontinuous transition to a singlet state at a larger value of the frustration parameter. In the ferrimagnetic phase we find a disorder point marking the onset of incommensurate real-space short-range spin-spin correlations.
Cite
@article{arxiv.cond-mat/9803150,
title = {Frustrated quantum Heisenberg ferrimagnetic chains},
author = {N. B. Ivanov and J. Richter and U. Schollwoeck},
journal= {arXiv preprint arXiv:cond-mat/9803150},
year = {2009}
}
Comments
16 pages (LaTex 2.09), 6 eps figures