Performance of local orbital basis sets in the self-consistent Sternheimer method for dielectric matrices of extended systems

TL;DR

This study evaluates the effectiveness of numerical pseudo-atomic orbital basis sets within the self-consistent Sternheimer method for calculating dielectric matrices of extended systems, showing promising accuracy and establishing a foundation for future electronic excitation research.

Contribution

It demonstrates that local orbital basis sets combined with the Sternheimer approach can accurately compute dielectric matrices, with minimal additional orbitals needed for convergence.

Findings

Dielectric matrices are within 1-3% of planewave reference calculations.

Polarization orbitals are essential for accuracy.

Few additional ta orbitals are needed when split norm is optimized.

Abstract

We present a systematic study of the performance of numerical pseudo-atomic orbital basis sets in the calculation of dielectric matrices of extended systems using the self-consistent Sternheimer approach of [F. Giustino et al., Phys. Rev. B 81 (11), 115105 (2010)]. In order to cover a range of systems, from more insulating to more metallic character, we discuss results for the three semiconductors diamond, silicon, and germanium. Dielectric matrices calculated using our method fall within 1-3% of reference planewaves calculations, demonstrating that this method is promising. We find that polarization orbitals are critical for achieving good agreement with planewaves calculations, and that only a few additional \zeta 's are required for obtaining converged results, provided the split norm is properly optimized. Our present work establishes the validity of local orbital basis sets and the self-consistent Sternheimer approach for the calculation of dielectric matrices in extended systems, and prepares the ground for future studies of electronic excitations using these methods.