The half-periodic Josephson effect in an s-wave superconductor - normal-metal - d-wave superconductor junction

Abstract

We show that in a long clean s-wave superconductor - normal-metal - d-wave superconductor junction the Josephson current is periodic in the superconducting phase difference with period instead of . The frequency of the ac Josephson effect and the period of the magnetic interference pattern become and respectively. This effect is due to the coexistence in the normal layer of current-carrying Andreev levels with phase differences and , and is robust with respect to finite temperature and weak elastic scattering.