%0 Journal Article
%T Low-energy excitations of spin-Peierls chains with modified bond-impurities
%A D. Augier
%A J. Riera
%A D. Poilblanc
%J Physics
%D 1999
%I arXiv
%R 10.1103/PhysRevB.61.6741
%X The introduction of modified bond-defects in spin-Peierls systems is investigated in a model of antiferromagnetic Heisenberg spin chains coupled to adiabatic phonons. Generically, new low-energy magnetic or non-magnetic excitations appear below the bulk spin gap energy. When two adjacent bonds are modified, these excitations can be interpreted in terms of boundstates of a soliton with the localized spin-1/2 located on the impurity site. It is shown that the confining potential occurs even in the case of {\it isolated} chains.
%U http://arxiv.org/abs/cond-mat/9908134v2