Faculté des sciences

Bound Excitons in Sr₂CuO₃

Kim, Kyung Wan ; Gu, G. D. ; Homes, C. C. ; Noh, T. W.

In: Physical Review Letters, 2008, vol. 101, no. 17, p. 177404

We investigated temperature dependent optical spectra of the one-dimensional chain compound Sr₂CuO₃. 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 blueshift and reveals additional sharp peaks at the gap. Even though many... Plus

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    Summary
    We investigated temperature dependent optical spectra of the one-dimensional chain compound Sr₂CuO₃. 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 blueshift and reveals additional sharp peaks at the gap. Even though many spectroscopic studies suggest that this material cannot have a bound exciton based on the one-dimensional extended Hubbard model, we attribute the additional sharp peaks to excitons, which come to exist due to the long-range Coulomb interaction.