Self-consistent ion transport simulation in carbon nanotube channels

We propose a method to self-consistently deal with polarisation effects in Monte Carlo particle simulations of charge transport. The systems of interest were membrane structures with a narrow (4-8 Å) carbon nanotube (CNT) channel in an aqueous environment. Due to computational limitations for Molecular Dynamics (MD) simulations, we extended the Transport Monte Carlo known from semiconductor simulations to ionic transport in water as a background medium. This method has been used successfully to compute transport rates of ions in biological channels but polarization effects on protein walls cannot be easily included self-consistently, due to the complexity of the structure. Since CNTs have a regular structure, it is practical to employ a self-consistent scheme that accounts for the charge redistribution on the channel wall when an external bias is applied or when the electrical field of a passing ion is screened out. Previous work has shown that this is necessary and the computationally efficient tight-binding (TB) approach developed there [1] is combined with transport Monte Carlo simulations in this work.