Effect of Electromagnetic Radiation on Nonideal Josephson Junctions

The method of numerical solution of equations is used within the resistive model to study the behavior of deviations of the current‒voltage characteristics of nonideal Josephson junctions from similar characteristics of ideal (standard) junctions. Nonideal Josephson junctions are those in which the current‒phase relation contains additional Josephson harmonics. The dependences of the amplitudes of current steps (Shapiro steps) on the power of external electromagnetic radiation is calculated. The shape of these dependences is shown to deviate from the corresponding dependences for ideal Josephson junctions. In addition, the paper examines the features of the occurrence of additional current steps on the current‒voltage characteristics of Josephson junctions and shows a possibility of their absence in the case of the presence of additional harmonics in the current‒phase relation. The obtained results prove that by analyzing the step structure of the current‒voltage characteristics it is possible to obtain information about the properties of Josephson junctions and superconductors that form them.