Superconductivity-induced optical changes for energies of 100Δ in the cuprates

M. Rübhausen; A. Gozar; M. V. Klein; P. Guptasarma; D. G. Hinks

doi:10.1103/PhysRevB.63.224514

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Superconductivity-induced optical changes for energies of 100Δ in the cuprates

M. Rübhausen, A. Gozar, M. V. Klein, P. Guptasarma, D. G. Hinks

DOI 10.1103/PhysRevB.63.224514 · Physical Review B

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Abstract

We present information on the temperature-dependent changes of the complex pseudodielectric function in the high-Tc superconductor Bi2Sr2CaCu2O8−δ by means of spectroscopic ellipsometry. We reveal the existence of three distinct spectral regions. Below 2 eV, there are changes in the dielectric function associated with the free-carrier response. In slightly underdoped compounds we find at around 3 eV a strong rise of ε2 below the temperature signifying the opening of a pseudogap (T*≈150 K) and an additional enhancement of similar strength below the superconducting transition (Tc=90 K). With overdoping, we find vanishing effects above Tc and a significant decrease in the Tc related effect. This behavior fits to the strong suppression of the antiferromagnetic correlations with increasing doping.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Bi2Sr2CaCu2O8-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	90	Pressure not reported	onset
Bi2Sr2CaCu2O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	90	Pressure not reported	onset