Evidence for very strong electron-phonon coupling in YBa_{2}Cu_{3}O_{6}

Guo-meng Zhao

doi:10.1103/PhysRevB.75.104511

paper

Evidence for very strong electron-phonon coupling in YBa_{2}Cu_{3}O_{6}

arXiv:cond-mat/0412262 · doi:10.1103/PhysRevB.75.104511

Abstract

From the observed oxygen-isotope shift of the mid-infrared two-magnon absorption peak of YBa $_{2}$ Cu $_{3}$ O $_{6}$ , we evaluate the oxygen-isotope effect on the in-plane antiferromagnetic exchange energy $J$ . The exchange energy $J$ in YBa $_{2}$ Cu $_{3}$ O $_{6}$ is found to decrease by about 0.9% upon replacing $^{16}$ O by $^{18}$ O, which is slightly larger than that (0.6%) in La $_{2}$ CuO $_{4}$ . From the oxygen-isotope effects, we determine the lower limit of the polaron binding energy, which is about 1.7 eV for YBa $_{2}$ Cu $_{3}$ O $_{6}$ and 1.5 eV for La $_{2}$ CuO $_{4}$ , in quantitative agreement with angle-resolved photoemission data, optical conductivity data, and the parameter-free theoretical estimate. The large polaron binding energies in the insulating parent compounds suggest that electron-phonon coupling should also be strong in doped superconducting cuprates and may play an essential role in high-temperature superconductivity.

4 pages, 1 figure

Evidence for very strong electron-phonon coupling in YBa_{2}Cu_{3}O_{6}

Abstract

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