Josephson junctions with silicon interlayer and arrays

Abstract

Dc and microwave properties of the Josephson sandwiches with amorphous silicon interlayer based on refractory materials have been investigated in a wide temperature range. The junctions have nonhysteresis I-V curves down to temperatures 2.2K. Reduced normal state resistance value can be varied in the range R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</inf> S = (5-5000) Ω μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> by changing the Si interlayer thickness; the I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</inf> R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</inf> products V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</inf> = (0.3-1) mV at the same time. Experimental data can be explained by resonance mechanism of electrical charge transferring through silicon interlayer. The transfer takes place along impurity resonant trajectories caused by the presence of the localized states in the forbidden band of the amorphous silicon. The mutual locking in the arrays has been investigated providing that there is a loop for ac Josephson currents. Due to a high V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</inf> value the mutual locking in the two junctions cell has been observed up to the voltage 1 mV which corresponds to submillimeter wavelength.