Element orbitals for Kohn-Sham density functional theory

TL;DR

This paper introduces element orbitals, a localized basis set derived from uniform basis functions, enabling accurate and efficient discretization of the Kohn-Sham Hamiltonian in density functional theory for various materials.

Contribution

The method automatically contracts uniform basis sets into localized element orbitals, achieving high accuracy with fewer basis functions per atom in DFT calculations.

Findings

Achieves meV accuracy for 3D dense systems

Applicable to both insulating and metallic materials

Uses a small number of basis functions per atom

Abstract

We present a method to discretize the Kohn-Sham Hamiltonian matrix in the pseudopotential framework by a small set of basis functions automatically contracted from a uniform basis set such as planewaves. Each basis function is localized around an element, which is a small part of the global domain containing multiple atoms. We demonstrate that the resulting basis set achieves meV accuracy for 3D densely packed systems with a small number of basis functions per atom. The procedure is applicable to insulating and metallic systems.