Local Potential Functional Embedding Theory of Molecular Systems: Localized Orbital-Based Embedding from an Exact...

Area of Science:

• Quantum Chemistry
• Condensed Matter Physics
• Computational Materials Science

Background:

• Density Matrix Embedding Theory (DMET) provides a framework for localized orbital-based quantum embedding.
• Accurate description of strongly correlated systems remains a challenge in electronic structure theory.
• Lattice Density Functional Theory (DFT) offers an alternative perspective for electronic structure calculations.

Purpose of the Study:

• To reformulate localized orbital-based quantum embedding from a lattice DFT perspective.
• To derive an in-principle exact formulation for any electronic Hamiltonian.
• To develop a practical embedding theory for strongly correlated systems.

Main Methods:

• Developed an exact formulation where localized orbital occupations act as the density.
• Derived an exact relationship between the local Hartree-exchange-correlation (Hxc) potential and the embedding chemical potential.
• Applied density-functional approximations to derive a self-consistent Local Potential Functional Embedding Theory (LPFET).

Main Results:

• Established a novel connection between the Hxc potential and fragment-specific embedding chemical potentials.
• Introduced LPFET, a practical embedding theory utilizing the local Hxc potential as the primary variable.
• Demonstrated LPFET's ability to significantly improve density profile descriptions in strongly correlated systems.

Conclusions:

• The developed LPFET offers a more accurate description of density profiles compared to previous embedding methods.
• The fragment-dependent embedding chemical potential expression is a key innovation of LPFET.
• This work provides a promising new avenue for studying strongly correlated electronic systems.