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Raman study of carrier-overdoping effects on the gap in high-Tc superconducting cuprates

T. Masui·M. Limonov·H. Uchiyama·S. Lee·S. Tajima·A. Yamanaka
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Abstract

Raman scattering in the heavily overdoped (Y,Ca)Ba_2Cu_3O_{7-d} (T_c = 65 K) and Bi_2Sr_2CaCu_2O_{8+d} (T_c = 55 K) crystals has been investigated. For the both crystals, the electronic pair-breaking peaks in the A_{1g} and B_{1g} polarizations were largely shifted to the low energies close to a half of 2Delta_0, Delta_0 being the maximum gap. It strongly suggests s-wave mixing into the d-wave superconducting order parameter and the consequent manifestation of the Coulomb screening effect in the B_{1g}-channel. Gradual mixing of s-wave component with overdoping is not due to the change of crystal structure symmetry but a generic feature in all high-T_c superconducting cuprates.

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T. Masui, M. Limonov, H. Uchiyama, S. Lee, S. Tajima, A. Yamanaka. 2003-08-07. Raman study of carrier-overdoping effects on the gap in high-Tc superconducting cuprates. https://doi.org/10.1103/physrevb.68.060506

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