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3.1.2 Starting voltage, Vs

The threshold voltage increases distinctly with Vs. In figure 11, which shows several histograms, Vt increases by almost a factor two as Vs is increased. The reason for this might have something to do with excess charges in the array. When the ramp starts at low Vs there is a negative current and a lot of charges are present in the array. When the voltage increases above zero there are charges already present in the array to start the current by positive and negative charge solitons10 annihilating each other, but when the ramp starts at high Vs there are charges left from the positive current in the array and to start the current solitons must be injected in the array, which requires higher energy.


Figure 11. Histograms for chip H7#43. The threshold voltage increases with the starting voltage of the ramp, Vs. This measurement was taken at T=50 mK, B=-1.5 mT and f=76.8 Hz.


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