Energy dependence of the Andreev reflection of YBa2Cu3O7−δ

摘要

Measurements of the energy dependence of the Andreev reflection have been performed on a Ag-YBa2Cu3O7−δ interface. The observation of the Andreev reflection indicates a ground state of zero-momentum pairs. It is shown that, in principle, the bulk Δ (electron pair potential) can be determined from the energy dependence of the Andreev reflection. In the present experiment, however, due to the limited mean free path of the electrons in the silver, only a lower limit of Δ was found.