Exciting: a full-potential all-electron package implementing density-functional theory and many-body perturbation...

Area of Science:

• Computational Physics
• Materials Science
• Quantum Chemistry

Background:

• Linearized augmented planewave (LAPW) methods are highly accurate for solving Kohn-Sham equations in density-functional theory (DFT).
• The exciting computer package implements these advanced numerical schemes for electronic structure calculations.

Purpose of the Study:

• To review the implementation of LAPW methods within the exciting all-electron, full-potential code.
• To highlight the versatility and accuracy of various basis sets for electronic structure calculations.
• To showcase the code's capabilities for both ground-state and excited-state properties.

Main Methods:

• Utilizes linearized augmented planewave plus local orbital (LAPW+lo) basis sets for high precision.
• Employs time-dependent DFT (TDDFT) in the linear-response regime for excited states.
• Incorporates many-body perturbation theory, including the GW approximation (G(0)W(0)) and Bethe-Salpeter equation (BSE).

Main Results:

• Demonstrates achieving microhartree accuracy with careful basis set selection.
• Successfully computes optical and electron-loss spectra for various materials.
• Provides accurate quasi-particle band structures and describes strongly bound excitons via BSE.

Conclusions:

• The exciting code offers a robust platform for high-accuracy electronic structure calculations.
• It enables comprehensive studies of material properties, from elastic constants to complex excitation spectra.
• The code is suitable for diverse applications in condensed matter physics and quantum chemistry.