The Chemical Control of Superconductivity in Bi2Sr2(Ca1¡ x Yx)Cu2O8+δ

R. S. Liu；I. J. Hsu；J. M. Chen；R. G. Liu

Chinese Journal of Physics

38卷2S期（2000 / 04 / 01）

225 - 230

英文

The chemical substitution of Y^3+ for Ca^2+ in Bi2Sr2(Ca1-x Yx)Cu2O8+δ leads to the overdoped, optimum doped and underdoped states. The hole distribution in the series compounds has been investigated by high-resolution O K-edge X-ray-absorption near-edge-structure (XANES) spectra. Near the O 1s edge, a well-prounced pre-edge peak with maximun at ～ 528.3 eV is found, which is ascribed to the excitations of O 1s electron to O 2p hole states located in the CuO2 planes. The intensity of the pre-edge peak decreases with the Y doping. This demonstrates that the chemical substitution of Y3+ for Ca2+ in Bi2Sr2(Ca1-x Yx)Cu2O8+δ gives rise to a decrease in hole concentration within the CuO2 planes.