Correlation between Cu valence, hole density and Tc of Bi2201, Bi2212 and Bi2223 superconductors

Pb-substitution effect on the electronic properties of Bi2201, Bi2212 and Bi2223 superconductors

“…4(b). It should be noted that the Pb valence has an assumed average formal valence of 3 + Consistent with previous data 12) and Mott-Hubbard theory, p increases with increasing v for the Pb-free Bi2212 phase. These results suggest that the holes are doped in the CuO 2 layer.…”

“…They revealed that for Pb-free Bi2201 (m = 1) and Bi2212 (m = 2) phases, the Hall coefficient roughly scales with the inverse of (v-2) measured from the formal valence, v. We previously examined the correlation between p measured by the Hall coefficient and v measured by iodometry for Pb-free Bi2201 and Pb-free Bi2212 phases. 12) In these phases, p scales with v, revealing a Mott-Hubbardlike character, which agrees well with the data by Maeda et al 6) Maeda et al revealed that for the Pb-substituted Bi2201 phase, the Hall coefficient deviates from the inverse of (v-2) measured from the formal valence. 6) Additionally, we found that p does not scale with v for Pb-substituted Bi2223.…”

“…The open and closed circles represent the Pb-free and Pb-substituted Bi2212 phase, respectively. Consistent with previous data12) and Mott-Hubbard theory, p increases with increasing v for the Pb-free Bi2212 phase. These results suggest that the holes are doped in the CuO 2 layer.On the other hand, the Pb-substituted Bi2212 phase shows a different trend.…”

“…6) Additionally, we found that p does not scale with v for Pb-substituted Bi2223. 12) These results suggest that holes are not doped into the CuO 2 plane for the Pb-substituted Bi2201 and Bi2223 phases. The deviation from Mott-Hubbard theory of the Pb-substituted Bi2201 and Bi2212 phases has not been explained clearly.…”