Anomalous effect of biased oscillating field on the switching behaviour: modulating friction of charge carriers in nanowires

Abstract

Ultra-low doped polypyrrole nanowires show characteristics of charge density waves (CDW) due to possible Wigner crystallization. The motion of CDW in these structurally discordered wires is expected to be different as CDW is not forming here due to underlying lattice. The results presented here show that the dc switching threshold voltage decreases rapidly with increasing ac bias, but the threshold current remains same. The ac component acts as an effective dc bias having value proportional to (ac amplitude)^1.5. Near the switching transition, the voltage fluctuates and shows repetitive downward spikes. The results show several similarities with the "stick-slip" motion and aging-rejuvenation competition observed in jamming near the sliding motion in mechanical friction. The results also suggest an increase of dynamic correlation length in the presence of ac bias.