Semi-empirical many-body formalism of optical absorption in nanosystems and molecules

TL;DR

This paper introduces a computationally efficient Green's function method combining GW approximation with tight-binding and Hubbard models to accurately predict optical absorption in nanostructures and molecules, improving agreement with experiments.

Contribution

It presents a semi-empirical many-body formalism that enhances optical property predictions for nanosystems using a scalable GW-based approach on simple electronic models.

Findings

Improved agreement with experimental optical absorption data for PAHs.

Method is applicable to various nanostructures within a mean-field electronic description.

Suitable for high-throughput screening of materials with desired optical features.

Abstract

A computationally efficient Green's function approach is developed to evaluate the optical properties of nanostructures using a GW formalism applied on top of a tight-binding and mean-field Hubbard model. The use of the GW approximation includes key parts of the many-body physics that govern the optical response of nanostructures and molecules subjected to an external electromagnetic field. Such description of the electron-electron correlation yields data that are in significantly improved agreement with experiments performed on a subset of polycyclic aromatic hydrocarbons (PAHs) considered for illustrative purpose. More generally, the method is applicable to any structure whose electronic properties can be described in first approximation within a mean-field approach and is amenable for high-throughput studies aimed at screening materials with desired optical properties.