Multiple Negative Differential Resistances in Nanofluidic Conical Pores: A Phenomenological Model.

Ionic flow nonlinear effects are helpful for sensing and signal processing in nanofluidic systems. Here, we develop a simple phenomenological model based on a distribution of Boltzmann-like electrical conductances to describe different forms of voltage-controlled negative differential resistance observed in charged conical nanopores. Multiple negative differential resistance phenomena show abrupt drops in the ionic current when the applied voltage exceeds a series of threshold voltages. We use the phenomenological model to describe the multiple states resulting from externally controlled salt precipitation at the conical pore tips. We consider both single- and multipore membranes, together with parallel and antiparallel arrangements of two membranes, as a function of the applied voltage, salt type, ionic concentration, and temperature.