Soliton interaction in coupled spin-Peierls chains

D. MASTROGIUSEPPE; C. GAZZA; A. DOBRY

ICTP, Trieste, Italia

Workshop; School and Workshop on Highly Frustrated Magnets and Strongly Correlated Systems: From Non-Perturbative Approaches to Experiments; 2007

ICTP (International Center of Theoretical Physics)

We reconsider the elementary excitations of quasi-one-dimensional spin-phonon systems taking into account the interchain coupling. It is expected that the effect of the interchain coupling will be to confine the spin one-half solitons corresponding to each isolated chain. We show that this is the case when the interchain coupling is not frustrated. In the frustrated case  we show that free solitons could be the elementary excitations of the coupled two-dimensional model. The case of an elastic interchain coupling is analyzed on a general energetic consideration. For the simplified two-chain problem we use DMRG calculations. In this case we take into account the magnetic interchain coupling. We show that the deconfinement mechanism is effective even when the antiferromagnetic interchain coupling is present. Our results could be relevant for a further experimental determination  of the magnetic spectra in the recently studied spin-Peierls system TiOCl.