c-axis Josephson tunneling in twinned and untwinned YBCO-Pb junctions

Article

关键词: ORDER-PARAMETER;    ENERGY-GAP;    SUPERCONDUCTING GAP;    PAIRING STATE;    YBA2CU3O7-DELTA;    SYMMETRY;    BI2SR2CACU2O8+DELTA;    SPECTROSCOPY;    ANISOTROPY;    MODEL;   

DOI  :  10.1103/PhysRevB.55.9088

来源: SCIE

【 摘 要 】

Within a microscopic two-band model of planes and chains with a pairing potential in the planes and off-diagonal pairing between planes and chains we find that the chains make the largest contribution to the Josephson tunneling current and that through them the d-wave part of the gap contributes to the current. This is contrary to the usual assumption that the d-wave part of the gap does not contribute to the c-axis Josephson current for incoherent tunneling into an s-wave superconductor and for a d-wave orthorhombic superconductor with a small s-wave component to its gap only the s-component contributes. It has been further argued that the effect of twins, in YBa2Cu3O7-delta (YBCO) would lead to cancellation between pairs of twins, and so the observation of a current in c-axis YBCO-Pb experiments is evidence against a d-wave-type order parameter. We argue that there is evidence that the two twin orientations are not necessarily equally abundant in call cases.

【 授权许可】

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