We report low temperature scanning tunneling spectroscopy (STS) studies on NdBa2Cu3O7-δ (Nd123) single crystals. Two characteristic spectra with a nearly ohmic background spectrum and a V-shaped background are observed on the cleaved surfaces. The former spectum shows an inhomogeneous distribution of a superconducting energy gap (2Δ) for STS differential conductance map. The latter shows a homogeneous distribution. It is probable that those differences are attributed to a tunneling current from different surface layers. The temperature dependence of tunneling conductance spectrum with a V-shaped background reveals that the superconducting gap disappears around Tc, and no pseudogap behavior exists above T c.
|ジャーナル||Journal of Superconductivity and Novel Magnetism|
|出版ステータス||Published - 2002|
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