Nonlinear hopping transport in ring systems and open channels

摘要

We study the nonlinear hopping transport in one-dimensional rings and openchannels. Analytical results are derived for the stationary current response toa constant bias without assuming any specific coupling to the external fields.It is shown that anomalous large effective jump lengths, as observed in recentexperiments by taking the ratio of the third order nonlinear and the linearconductivity, can occur already in ordered systems. Rectification effects dueto site energy disorder in ring systems are expected to become irrelevant forlarge system sizes. In open channels in contrast, rectification effects occuralready for disorder in the jump barriers and do not vanish in thethermodynamic limit. Numerical solutions for a sinusoidal bias show that thering system provides a good description for the transport behavior in the openchannel for intermediate and high frequencies. For low frequencies temporalvariations in the mean particle number have to be taken into account in theopen channel, which cannot be captured in the more simple ring model.