Overlapping fragments method for electronic structure calculation of large systems

TL;DR

This paper introduces an overlapping fragments method for efficiently calculating the electronic structure of very large systems with tens of thousands of atoms, leveraging parallel computing and linear scaling.

Contribution

The paper presents a novel overlapping fragments approach that enables linear-scaling electronic structure calculations for large systems, suitable for parallel computing architectures.

Findings

Method scales linearly with system size for fixed energy intervals.

Effective for systems with tens of thousands of atoms.

Successfully applied to amorphous polymers using DFT-based charge patching.

Abstract

We present a method for the calculation of electronic structure of systems that contain tens of thousands of atoms. The method is based on the division of the system into mutually overlapping fragments and the representation of the single-particle Hamiltonian in the basis of eigenstates of these fragments. In practice, for the range of system size that we studied (up to tens of thousands of atoms), {the dominant part of the calculation scales} linearly with the size of the system when all the states within a fixed energy interval are required. The method is highly suitable for making good use of parallel computing architectures. We illustrate the method by applying it to diagonalize the single-particle Hamiltonian obtained using the density functional theory based charge patching method in the case of amorphous alkane and polythiophene polymers.