Rae A I
School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Phys Rev Lett. 2000 Mar 6;84(10):2235-8. doi: 10.1103/PhysRevLett.84.2235.
Recent experimental studies of Josephson tunneling between single crystals of Bi2Sr2CaCu2O8+x (BSCCO) and lead (Pb) films have revealed small, but finite, critical currents along the c axis of BSCCO, despite this being forbidden by symmetry. We show that the known anisotropy of the Pb order parameter would allow quite strong coupling between single crystals of BSCCO and Pb if the tunneling direction were along the BSCCO c axis and the [110] direction of the Pb crystal. This mechanism could account for the experimental results on granular Pb films if there is a few percent preferred orientation in the films. All the current experimental evidence is therefore consistent with BSCCO being a pure d-wave superconductor.
最近对Bi2Sr2CaCu2O8+x（BSCCO）单晶与铅（Pb）薄膜之间约瑟夫森隧穿的实验研究表明，尽管从对称性角度来看这是被禁止的，但沿BSCCO的c轴仍存在小而有限的临界电流。我们表明，如果隧穿方向沿着BSCCO的c轴和Pb晶体的[110]方向，已知的Pb序参量各向异性将允许BSCCO单晶与Pb之间有相当强的耦合。如果薄膜中存在百分之几的择优取向，这种机制可以解释关于颗粒状Pb薄膜的实验结果。因此，目前所有的实验证据都与BSCCO是纯d波超导体这一观点一致。
