Quasiparticle self-consistent GW method for the spectral properties of complex materials

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• The GW approximation is a powerful many-body perturbation theory for electronic structure calculations.
• The standard G0W0 method, a perturbative approach, relies heavily on the initial mean-field approximation.
• G0W0 often struggles with accurately predicting band gaps in semiconductors and insulators.

Purpose of the Study:

• To introduce and evaluate the quasiparticle self-consistent GW (QSGW) approximation.
• To address the limitations and inaccuracies of the conventional G0W0 scheme.
• To provide a more reliable method for predicting spectral properties of diverse materials.

Main Methods:

• Application of the GW approximation within a quasiparticle self-consistent scheme (QSGW).
• Comparison of QSGW results with the G0W0 approximation and experimental data.
• Focus on overcoming the dependence on the initial mean-field and handling the non-Hermitian self-energy.

Main Results:

• QSGW successfully corrects the band gaps of small-gap semiconductors and large-gap insulators.
• The method accurately predicts spectral properties for challenging materials like transition metal oxides.
• QSGW demonstrates improved accuracy over G0W0 without the full complexity of self-consistent GW.

Conclusions:

• QSGW offers a robust and computationally feasible alternative to G0W0 for electronic structure calculations.
• This method significantly enhances the predictive power of GW theory for a broader range of materials.
• QSGW is a valuable tool for materials discovery and understanding electronic properties.