T. Yamamoto et al., STUDY OF THE TUNNELING CHARACTERISTICS OF BA1-XKXBIO3 SUPERCONDUCTINGTHIN-FILMS BASED ON THE GAP-ENERGY DISTRIBUTION MODEL, JPN J A P 1, 35(2A), 1996, pp. 595-600
The broadening of the gap edge in the conductance-voltage (dI/dV-V) ch
aracteristics for native-barrier Ba1-xKxBiO3-gold (BKBO//Au) and MgO-b
arrier Ba1-xKxBiO3-gold (BKBO/MgO/Au) junctions was investigated by us
ing a gap-energy distribution model where the inhomogeneity of the ene
rgy gap Delta at the junction interface was taken into consideration.
It was demonstrated that the broadening of the dI/dV-V curves and thei
r temperature dependence (T < 2T(C)/3) in both junctions could be expl
ained by assuming the Gaussian distribution of gap energies (at T = 0
K) with Delta(0)(0) = 3.1 meV; delta Delta = 0.9 meV for the BKBO//Au
junction and Delta(0)(0) = 3.5 meV, delta Delta = 1.1 meV for the BKBO
/MgO/Au junction, where Delta(0)(0) and delta Delta represent the cent
er point and the width of the distribution, respectively. It was found
that the value delta Delta could be regarded as a criterion for the q
uality of the tunneling junction.