Interaction confinement in nanoscale ion transport

Fluid transport at the nanoscale is fundamental to various processes, from neurotransmission to ultrafiltration. Yet, it is only recently that well-controlled channels with cross-sections of a few molecular diameters became accessible experimentally [1]. When aqueous electrolytes are confined within such channels, the Coulomb interactions between the dissolved ions are reinforced due to dielectric contrast at the channel walls: we call this effect interaction confinement. Interaction confinement leads to ionic correlations, which we have previously shown to result in several non-linear transport phenomena, including ionic Coulomb blockade and memristor effects [2,3]. In this talk, I will show that interaction confinement can be tuned by the electronic properties of the channel wall material. I will introduce a new formalism, based on surface response functions, that links the effective Coulomb interactions within a channel to the wall's band structure, described to any desired level of precision [4]. These results provide a quantitative approach to controlling nanoscale ion transport through the choice of the channel wall material.