Novel phenomena in Josephson nanostructures, резюме
"Short review of our recent results on coupled Josephson junctions is presented. Particularly, a variation of longitudinal plasma wavelength under external electromagnetic radiation and its experimental testing is discussed. We demonstrate the principal difference in the reaction of the system of coupled junctions to the external radiation in comparison with the case of single Josephson junction. The IV-characteristics of a Josephson junction under external electromagnetic radiation show the devil’s staircase within different bias current intervals. It is found that the observed steps form very precisely continued fractions. We discuss an algorithm for the appearance and detection of sub-harmonics with increasing radiation amplitude and demonstrate that the staircase structures registered in many well-known experiments and by simulations form also the continued fractions. We study an effect of external radiation on the dynamics of the Josephson junction shunted by an LC circuit. When the Josephson frequency is equal to the frequency of the circuit, additional stable resonant circuit branches appear in the IV-characteristic of the junction. We show that the amplitude dependence of the Shapiro step width crucially changes when the Shapiro step is on the resonant circuit branch. These effects might give very important advantages for methods and technologies that exploit the response of Josephson junctions to microwave fields."