Optical absorption spectra in SrCu2O3 two-leg spin ladder -: art. no. 134432

We calculate the phonon-assisted optical-absorption spectra in SrCu2O3 two-leg spin-ladder systems. The results for two models proposed for SrCu2O3 are compared. In the model including the effects of a cyclic four-spin interaction, the shoulder structure appears at similar to978 cm(-1) and the peak appears at similar to1975 cm(-1) in the spectrum for polarization of the electric field parallel to the legs. In the other model which describes a pure two-leg ladder, the peak appears around the lower edge of the spectrum at similar to1344 cm(-1). The feature can be effective in determining the proper model for SrCu2O3.