Generation of ferromagnetic bonds in disordered antiferromagnetic spin-1 chains with biquadratic couplings

摘要

The interplay between effects of disorder and correlation often gives rise to interesting new physics. In this paper we demonstrate that in a disordered spin-1 chain with both Heisenberg and biquadratic couplings, effective ferromagnetic couplings can be generated even if all the original couplings are antiferromagnetic, an effect that would not occur without randomness. Microscopic origin as well as the physical consequences of this effect are discussed.