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[en] Parametric amplification of a high-frequency radiation by point-like Josephson junctions in the cavity has been studied within a resistive model. It is shown numerically and analytically that near the subharmonic steps of the current–voltage characteristic there are areas of amplification of electromagnetic radiation. An one-dimensional array of the Josephson point junctions connected in series is treated. It is shown that the junctions in the array near the subharmonic steps of current–voltage characteristic are nonsynchronized and, accordingly, the amplification regions near the subharmonic steps of the array are missing.
[en] Partial electron localization in a finite-size superlattice placed in an electric field is considered. The role of electric field in forming of quasilocalized states is investigated. A quantitative criterion for the degree of partial localization is suggested based on analysis of maximal probability density of finding an electron at a given point. It is found that with increase in the electric field the degree of localization does not increase monotonically. Furthermore, the localization is affected stronger by the amplitude of superlattice potential than by the electric field.
[en] Generation of direct current in a semiconductor superlattice under the action of an ac bichromatic field is considered in the most general case of an arbitrary ratio of the frequencies of the fields being mixed. It is shown that this effect is of parametric origin associated with oscillations of the electron effective mass in the miniband of the superlattice.
[en] Simple formulas describing terahertz absorption and gain in a semiconductor superlattice irradiated by a microwave pump field are derived for the case when the signal frequency is a half harmonic of the pump. A simple qualitative analysis provides a geometric interpretation of the derived formulas, which can be used to determine if gain is feasible
[en] The thermopower of asymmetrical quantum wires and constrictions in an arbitrarily directed magnetic field is investigated. An analytic expression convenient for analysing the thermopower is obtained. The oscillations in the thermopower are studied. It is shown that the thermopower as a function of a magnetic field can undergo Aharonov-Bohm and Shubnikov-de Haas oscillations
[en] The thermopower of two-dimensional parabolic quantum wires and quantum contacts in magnetic field is investigated. We obtain a convenient analytic formula for the thermopower of these structures. The temperature dependence of the thermopower is studied and the influence of the magnetic field on the thermopower is examined. Oscillations in the thermopower are investigated