Optimized norm-conserving Vanderbilt pseudopotentials

TL;DR

This paper introduces an optimized approach for constructing norm-conserving Vanderbilt pseudopotentials, improving convergence and accuracy in plane-wave calculations for various solids.

Contribution

It develops a new formulation for optimizing fully-nonlocal two-projector pseudopotentials, including positive-energy states and enhanced continuity, advancing pseudopotential design.

Findings

Enhanced pseudopotentials show better convergence.

Accurate lattice constants and bulk moduli across diverse solids.

Compatibility with systematic optimization methods.

Abstract

Fully-nonlocal two-projector norm-conserving pseudopotentials are shown to be compatible with a systematic approach to the optimization of convergence with the size of the plane-wave basis. A new formulation of the optimization is developed, including the ability to apply it to positive-energy atomic scattering states, and to enforce greater continuity in the pseudopotential. The generalization of norm-conservation to multiple projectors is reviewed and recast for the present purposes. Comparisons among the results of all-electron and one- and two-projector norm-conserving pseudopotential calculations of lattice constants and bulk moduli are made for a group of solids chosen to represent a variety of types of bonding and a sampling of the periodic table.