Low-energy excitations of spin-Peierls chains with modified bond impurities
David Augier, José A. Riera, Didier Poilblanc
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 nonmagnetic excitations appear below the bulk spin gap energy. When two adjacent bonds are modified, these excitations can be interpreted in terms of bound states 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 isolated chains.
arXiv:cond-mat/9908134•Physical review. B, Condensed matter•Mar 1, 2000•10 citations