Direct Coupling Between Magnetism and Superconducting Current in the Josephson φ₀ Junction

We study the proximity effect between conventional superconductor and magnetic normal metal with a spin-orbit interaction of the Rashba type. Using the phenomenological Ginzburg-Landau theory and the quasiclassical Eilenberger approach it is demonstrated that the Josephson junction with such a metal as a weak link has a special nonsinusoidal current-phase relation. The ground state of this junction is characterized by the finite phase difference φ₀, which is proportional to the strength of the spin-orbit interaction and the exchange field in the normal metal. The proposed mechanism of the φ₀ junction formation gives a direct coupling between the superconducting current and the magnetic moment in the weak link. Therefore the φ₀ junctions open interesting perspectives for the superconducting spintronics.