Josephson Effect in Point Contacts Between Two-Band Superconductors

The microscopic theory of Josephson effect in point contacts between two-band superconductors is developed. The general expression for the Josephson current, which is valid for arbitrary temperatures, is obtained. We considered the dirty superconductors with interband scattering, which produces the coupling of the Josephson currents between different bands. The influence of phase shifts and interband scattering rates in the banks is analyzed near critical temperature T c . It is shown that for some values of parameters the critical current can be negative, which means the π-junction behavior.