A configuration interaction approach to solve the Anderson impurity model; applications to elemental Ce

Area of Science:

• Condensed matter physics
• Computational materials science
• Quantum chemistry

Background:

• Accurate calculations of strongly correlated materials are computationally demanding.
• Conventional methods like exact diagonalization face significant efficiency challenges.
• Understanding the electronic structure of materials under pressure is crucial.

Purpose of the Study:

• To present an efficient and accessible solver for dynamical mean field theory (DMFT).
• To utilize configuration interaction (CI) for improved computational efficiency in DMFT.
• To analyze the electronic structure evolution of cerium under lattice compression.

Main Methods:

• Development of an efficient solver for DMFT using configuration interaction (CI).
• Comparison of the CI-based DMFT solver with traditional exact diagonalization methods.
• Application of the solver to study cerium in its gamma, alpha, and epsilon phases.

Main Results:

• The CI-based DMFT solver demonstrates improved efficiency over exact diagonalization.
• The electronic structure of cerium evolves from localized 4f electrons in gamma-Ce to itinerant 4f electrons in epsilon-Ce.
• The alpha-phase of cerium is identified as a strongly correlated phase featuring a Kondo singlet.

Conclusions:

• The developed CI-DMFT solver provides an accessible, open-source tool for condensed matter physics research.
• The study provides insights into the Mott transition in cerium, modulated by the Kondo singlet formation in the alpha-phase.
• This work facilitates the study of complex electronic behaviors in strongly correlated systems on standard computing hardware.