Effects of Quantum Tunneling in Metal Nano-gap on Surface-Enhanced Raman Scattering

TL;DR

This paper investigates how quantum tunneling between metallic plates affects surface-enhanced Raman scattering, revealing that tunneling reduces enhancement when separation is below 0.6 nm, with dependence on local field and separation.

Contribution

It provides a detailed analysis of quantum tunneling effects on SERS enhancement using time-dependent density functional theory, highlighting the critical separation threshold.

Findings

Quantum tunneling depends on separation and local field.

Tunneling reduces SERS enhancement below 0.6 nm separation.

Numerical results quantify tunneling impact on nanoparticle interstices.

Abstract

The quantum tunneling effects between two metallic plates are studied using the time dependent density functional theory. Results show that the tunneling is mainly dependent on the separation and the initial local field of the interstice between plates. The smaller separation and larger local field, the easier the electrons tunnels through the interstice. Our numerical calculation shows that when the separation is smaller than 0.6 nm the quantum tunneling dramatically reduce the enhancing ability of interstice between nanoparticles.