Coulomb Blockade in Angstrom-scale latent ion track channels

TL;DR

This paper reports the discovery of ionic Coulomb blockade in angstrom-scale latent ion channels, revealing unique voltage-dependent conductance behavior and providing an analytical model to understand ion transport at this scale.

Contribution

It introduces the first experimental observation of Coulomb blockade in latent ion channels of 0.6 nm diameter and develops an analytical model based on Kramers' escape theory.

Findings

Channels are nearly non-conductive at low voltage due to ion binding.

Conductance increases with voltage as bound ions are released.

The analytical model fits experimental data and offers new insights into ion transport.

Abstract

When channels were scaled down to the size of hydrated ions, ionic Coulomb blockade was discovered. However, the experimental CB phenomenon was rarely reported since Feng et.al., discovered in MoS2 nanopore. By using latent-track membranes with diameter of 0.6 nm, we found the channels are nearly non-conductive in small voltage due to the blockade of cations bound at surface, however turns to be conductive as rising of voltage due to releasing of bound ions, which differs from the mechanisms in MoS2 nanopore. By Kramers' escape framework, we rationalized an analytical equation to fit experimental results, uncovering new fundamental insights of ion transport in the smallest channels.