Doping dependence of the superconducting gap in Bi2Sr2CaCu2O8+δ

K. C. Hewitt; J. C. Irwin

doi:10.1103/PhysRevB.66.054516

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Doping dependence of the superconducting gap in Bi2Sr2CaCu2O8+δ

K. C. Hewitt, J. C. Irwin

DOI 10.1103/PhysRevB.66.054516 · Physical Review B

T1

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Abstract

Bi2Sr2CaCu2O8+δ crystals with varying hole concentrations (0.12<p<0.23) were studied to investigate the effects of doping on the symmetry and magnitude of the superconducting gap [Δ(k)]. Electronic Raman scattering experiments that sample regions of the Fermi surface near the diagonal (B2g) and principal axes (B1g) of the Brillouin zone have been utilized. The frequency dependence of the Raman response function χ″ at low energies [ω<Δ(k)] is found to be linear for B2g and cubic for B1g (T<Tc). The latter observations have led us to conclude that the doping dependence of the superconducting gap is consistent with dx2−y2 symmetry, for slightly underdoped and overdoped crystals. Studies of the pair-breaking peak found in the B1g spectra demonstrate that the magnitude of the maximum gap (|Δmax|) decreases monotonically with increasing hole doping, for p>0.12. Based on the magnitude of the B1g renormalization, it is found that the number of quasiparticles participating in pairing increases monotonically with increased doping. On the other hand, the B2g spectra show a weak “pair-breaking peak” that follows a paraboliclike dependence on hole concentration, for 0.12<p<0.23.

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.	30	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	51	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	70	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	82	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	85	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	86	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	90.5	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	89	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	87	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	83	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	70	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	55	Pressure not reported	unknown