Truncation of Periodic Image Interactions for Confined Systems

TL;DR

This paper introduces a method to truncate Coulomb interactions in periodic first-principles calculations, effectively reducing artificial image effects in confined systems like 2D GaN sheets, leading to more accurate and converged results.

Contribution

A general approach for truncating Coulomb interactions that removes image effects and improves convergence in calculations of confined electronic systems.

Findings

Successfully applied to 2D GaN sheets

Achieved well-converged quasiparticle and exciton states

Reduced computational cost with modest-sized cells

Abstract

First principles methods based on periodic boundary conditions are used extensively by materials theorists. However, applying these methods to systems with confined electronic states entails the use of large unit cells in order to avoid artificial image interactions. We present a general approach for truncating the Coulomb interaction that removes image effects directly and leads to well converged results for modest-sized periodic cells. As an illustration, we find the lowest-energy quasiparticle and exciton states in two-dimensional hexagonal GaN sheets. These sheets have been proposed as parent materials for single-walled GaN nanotubes which may be of interest for optoelectronics.