Screening and antiscreening in fullerene-like cages:dipole-field amplification with ionic nanocages

TL;DR

This study explores how ionic nanocages can amplify dipole fields through antiscreening effects, enabling nanoscale electrostatic control without external fields, with implications for nanomaterials design.

Contribution

It reveals that ionic nanocages can induce antiscreening and act as dipole-field amplifiers, a novel finding in nanoscale electrostatic manipulation.

Findings

Screening varies with cage bonding type, maximum in covalent cages.

Ionic cages exhibit antiscreening, enhancing dipole fields.

Potential to tune nanocage dipole moments and generate nanoscale electrostatic fields.

Abstract

We investigate from first principles screening effects in endohedral complexes when small molecules, characterized by a finite electronic dipole moment, such as HF, LiF, NaCl, and H$_2$O, are encapsulated into different nanoscale cages. We find that screening effects crucially depend on the nature of the intramolecular bonds of the cage: screening is maximum in covalent-bond carbon nanocages, while it is reduced in partially-ionic ones. Interestingly, in the case of the ionic-bond nanocages, an antiscreening effect is observed: due to the relative displacement of positive and negative ions, induced by the dipole moment of the encapsulated molecule, these cages act as dipole-field amplifiers. Our results open the way to the possibility of tuning the dipole moment of nanocages and of generating electrostatic fields at the nanoscale without the aid of external potentials. Moreover, we can expect some transferability of the observed screening effects also to nanotubes and 2D materials.