# Efficient calculation of electronic structure using O(N) density functional theory

## TL;DR

This paper introduces a scalable method combining density functional theory and an eigenproblem solver to efficiently compute electronic structures of large systems with over 10,000 atoms, maintaining high accuracy.

## Contribution

It presents a novel integration of Conquest DFT code with the Sakurai-Sugiura eigenproblem solver for large-scale electronic structure calculations.

## Key findings

- Successfully applied to hydrated DNA, P2 molecules, and Ge hut clusters.
- Achieved high accuracy and efficiency for systems with over 10,000 atoms.
- Demonstrated practical applicability in large-scale systems.

## Abstract

We propose an efficient way to calculate the electronic structure of large systems by combining a large-scale first-principles density functional theory code, Conquest, and an efficient interior eigenproblem solver, the Sakurai-Sugiura method. The electronic Hamiltonian and charge density of large systems are obtained by \conquest and the eigenstates of the Hamiltonians are then obtained by the Sakurai-Sugiura method. Applications to a hydrated DNA system, and adsorbed P2 molecules and Ge hut clusters on large Si substrates demonstrate the applicability of this combination on systems with 10,000+ atoms with high accuracy and efficiency.