Theoretical simulations for the effect of lattice vibration on the transport properties of biological nanowires

Bacterial nanowires in biological systems have evolved over time to efficiently conduct electricity which facilitates extracellular and interspecies electron transfer (ET) that sustains biological respiration. These nanowires often have complex structures making it difficult to predict conductivities, even the bandgap can be predicted through density functional calculations. The electron or hole transport is determined by their hopping processes over localized states at the bottom of conduction bands or top of the valence bands. Using a tight biding model Hamiltonian, we examine the diffusing of wave pockets through a one-dimensional lattice with randomized on-site and hopping energies. This mimics the conduction of carries through biological nanowires with mixed coherent-incoherent transport mechanisms. Unexpectedly, we found that increasing the rate of rerandomization of the on-site and/or hopping energies during the electron propagating steps leads to increases in electron diffusion. This indicates that vibrations in biological nanowires are beneficial for enhance their conductivities. Results of molecular dynamics simulations and density functional calculations will also be discussed.