Scanning tunneling microscopy/spectroscopy (STM/STS) studies on the slightly overdoped Pb-substituted Bi2Sr2CuO 6+δ (Bi1.75Pb0.32Sr 1.91CuO6+δ) with Tc ∼ 19.5 K have been performed at 4.6 K in the modulation-free Bi(Pb)-O plane. Almost all dI/dV tunneling spectra exhibit clear peaks on both sides of the energy gap, in contrast to the lanthanoid (Ln) substituted Bi2201 with the similar doping level in which V-shape spectra without peaks have been partially observed. The energy gap Δs distributes in the range from ∼5 meV to ∼20 meV which is much smaller than Ln-Bi2201 with the similar doping level. It is found that the high-energy region of Δs disappears in the slightly overdoped Pb-substituted Bi2Sr2CuO6+δ.
ASJC Scopus subject areas
- General Physics and Astronomy