Electronic and optical properties of carbon nanodisks and nanocones

TL;DR

This theoretical study explores the electronic and optical properties of carbon nanodisks and nanocones, revealing size-dependent charge distributions and polarization-sensitive absorption spectra.

Contribution

It provides a detailed analysis of electronic densities and optical absorption in nanostructures with varying sizes and topologies using a tight-binding model.

Findings

Charge localization at cone apices and edges

Edge states dominate near the Fermi level in large structures

Absorption spectra depend on photon polarization in the infrared

Abstract

A theoretical study of the electronic properties of nanodisks and nanocones is presented within the framework of a tight-binding scheme. The electronic densities of states and absorption coefficients are calculated for such structures with different sizes and topologies. A discrete position approximation is used to describe the electronic states taking into account the effect of the overlap integral to first order. For small finite systems, both total and local densities of states depend sensitively on the number of atoms and characteristic geometry of the structures. Results for the local densities of charge reveal a finite charge distribution around some atoms at the apices and borders of the cone structures. For structures with more than 5000 atoms, the contribution to the total density of states near the Fermi level essentially comes from states localized at the edges. For other energies the average density of states exhibits similar features to the case of a graphene lattice. Results for the absorption spectra of nanocones show a peculiar dependence on the photon polarization in the infrared range for all investigated structures.