Permanent polarization of small metallic particles

TL;DR

This paper investigates how residual surface charges in metallic nanoparticles lead to a permanent electric dipole moment that scales linearly with particle size, highlighting size-dependent polarization effects.

Contribution

It demonstrates that small metallic particles exhibit a size-dependent permanent polarization due to surface charge fluctuations, a phenomenon not previously characterized.

Findings

Dipole moment increases linearly with particle size.

Surface charge fluctuations cause strong particle-to-particle variability.

Residual surface charges induce permanent polarization in metallic nanoparticles.

Abstract

Electric charge density in a metallic nanoparticle fluctuates due to inhomogeneities of various kinds. While in the bulk these fluctuations are compensated via Thomas--Fermi screening, residual surface charges give rise to a permanent electric dipole moment. We show that this dipole moment increases linearly with particle size, and fluctuates strongly from particle to particle