Bound Excitons inSr2CuO3

K. W. Kim, G. D. Gu, C. C. Homes, T. W. Noh
2008 Physical Review Letters  
We investigated temperature dependent optical spectra of the one-dimensional chain compound Sr_2CuO_3. The charge transfer transition polarized along the chain direction shows a strongly asymmetric line shape as expected in one-dimensional extended Hubbard model. At low temperature the charge transfer peak shows a large blue shift and reveals additional sharp peaks at the gap. Even though many spectroscopic studies suggest that this material can not have a bound exciton based on the
more » ... nal extended Hubbard model, we attribute the additional sharp peaks to excitons, which come to exist due to the long range Coulomb interaction.
doi:10.1103/physrevlett.101.177404 pmid:18999786 fatcat:3ln2dcipfjeirpyp7axmm2q3j4