DYNAMICS OF OVERDAMPED JOSEPHSON-JUNCTIONS DRIVEN BY A SQUARE-WAVE PULSE

The periodic solutions of an overdamped Josephson junction driven by a square-wave pulse were found. Unlike those driven by a sinusoidal ac current, the integer step widths of a Josephson junction driven by a s quare-wave pulse train are reduced with increasing ac current frequenc y. The maximum value of any non-zero step width approaches 2I(c), wher e I-c is the critical current, by decreasing either the pulse repetiti on rate or the pulse duration time. The characteristic features of any integer step are almost identical and we give an explanation of this. (C) 1998 American Institute of Physics.