Self-consistent embedding theory for locally correlated configuration interaction wave functions in condensed matter

Area of Science:

• Computational Chemistry
• Materials Science
• Condensed Matter Physics

Background:

• Accurate electronic structure calculations are crucial for understanding material properties.
• Periodic metallic systems with localized features pose challenges for traditional methods.
• Density-based embedding strategies offer a way to treat complex systems by dividing them into smaller parts.

Purpose of the Study:

• To present new developments in a density-based embedding strategy for localized features in periodic metallic systems.
• To incorporate ultrasoft pseudopotentials and handle dynamical correlation effects.
• To validate the embedding approach with realistic physical and chemical systems.

Main Methods:

• Decomposition of the total system into an embedded cluster and a fixed background density.
• Modeling the background effect as a one-electron potential derived from density functional theory (DFT).
• Self-consistent determination of the embedding potential and inclusion of multireference singles and doubles configuration interaction (MRSDCI) for dynamical correlation.

Main Results:

• A strategy for consistent incorporation of ultrasoft pseudopotentials was developed.
• A numerically stable method for achieving self-consistency in the embedding potential was presented.
• The embedding approach accurately predicted the spin-compensated ground state for Co adsorption on a Cu surface, outperforming standard Kohn-Sham DFT.

Conclusions:

• The developed density-based embedding strategy provides an accurate and efficient method for electronic structure calculations in complex metallic systems.
• The approach successfully models localized features and dynamical correlation effects.
• This method offers a significant improvement over standard DFT for certain challenging systems, as demonstrated by the Co/Cu adsorption case.