Quantized voltage plateaus in Josephson-junction arrays: A numerical study

摘要: We study numerically the quantized voltage plateaus in an N\ifmmode\times\else\texttimes\fi{}N array of resistively shunted Josephson junctions subjected to a combined dc and ac applied current ${\mathit{I}}_{\mathrm{dc}}$+${\mathit{I}}_{\mathrm{ac}}$sin(2\ensuremath{\pi}\ensuremath{\nu}t), transverse magnetic field equal p/q==f flux quanta per plaquette (p q relatively prime integers). With periodic boundary conditions, we find at all voltages satisfying 〈V〉=nNh\ensuremath{\nu}/(2eq), where n is integer, angular brackets 〈...〉 denote time average. free additional steps 〈V〉=Nh\ensuremath{\nu}/(4eq) sometimes appear. For f=1/5 2/5, motion vortex lattice on steps. At both fields, every step, moves integer number constants cycle field. zero finite field, width varies sinusoidally with ${\mathit{I}}_{\mathrm{ac}}$, manner reminiscent that seen single junctions. given current, ``melt'' temperature no higher than transition underlying same current. On steps, time-dependent across has strong harmonics multiples fundamental frequency. Off power spectrum apparently broad band possible subharmonic structure.