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Surface-charge governed ionic blockade in angstrom-scale latent-track channels
Yanbo Xie1,2, Deli Shi2, Wenhui Wang2
1School of Aeronautics and Institute of Extreme Mechanics, Northwestern Polytechnical University, Xi'an, 710072, China. ybxie@nwpu.edu.cn.
Nanoscale
|May 16, 2023
Summary
Ionic transport in angstrom-scale channels is blocked by surface charge at low voltage but becomes conductive with increasing voltage. This study reveals new insights into ion transport governed by surface charge effects.
Area of Science:
- Physics
- Chemistry
- Materials Science
Background:
- Coulomb interactions intensify in confined spaces, leading to unique phenomena.
- Understanding ion transport in angstrom-scale channels is crucial for nanotechnology and energy applications.
Purpose of the Study:
- To investigate the mechanism of ionic transport blockade in angstrom-scale channels.
- To differentiate this blockade from established phenomena like Coulomb blockade and Wien effects.
- To develop a model explaining ion transport governed by surface charge in confined environments.
Main Methods:
- Fabrication and characterization of latent-track angstrom-scale channels.
- Electrical measurements of ionic transport under varying voltage conditions.
- Application of Kramers' escape framework to model ion dynamics.
Main Results:
- Observed a voltage-dependent blockade of ionic transport, distinct from Coulomb blockade.
- Identified surface-bound cations as the cause of non-conductivity at low voltages.
- Demonstrated a transition to conductive and eventually ohmic behavior with increased voltage.
- Developed an analytical equation based on Kramers' escape framework to describe experimental data.
Conclusions:
- Surface charge governs ionic transport in angstrom-scale channels, leading to a novel blockade mechanism.
- The findings provide fundamental insights into ion transport in nanoscale confinement.
- The developed model offers a predictive tool for designing and optimizing nanoscale ionic devices.
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