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The oxygen isotope effect in the ab-plane reflectance of underdoped YBa_2Cu_3O_{7-delta}

N. L. Wang·T. Timusk·J. P. Franck·P. Schweiss·M. Braden·A. Erb
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Abstract

We have measured the effect of oxygen isotope substitution on the ab-plane reflectance of underdoped YBCO. The frequency shift of the transverse optic phonons due to the substitution of O-16 by O-18 yields an isotope effect of the expected magnitude for copper-oxygen stretching modes with alpha=0.5 +- 0.1. The reflectance shoulder at 400 - 500 cm^-1 shows a much smaller exponent of alpha=0.1 +- 0.1 in the normal state and alpha=0.23+- 0.1 in the superconducting state. These observations suggest that the shoulder is of electronic origin and not due to a phonon mode as has been suggested recently.

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N. L. Wang, T. Timusk, J. P. Franck, P. Schweiss, M. Braden, A. Erb. 2002-01-26. The oxygen isotope effect in the ab-plane reflectance of underdoped YBa_2Cu_3O_{7-delta}. https://doi.org/10.1103/physrevlett.89.087003

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