Strongly Interacting Electrons in a Single Particle Framework.

Nicholas Harrison

Department of Chemistry, Imperial College London, London SW7 2AZ, UK

The common knowledge of the 1980’s held that theory failed in the so-called strongly correlated systems exemplified by Mott-insulators. For this reason the discovery of high-temperature superconductivity in the cuprates and giant magnetoresistance in the manganates generated a crisis in predictive materials modeling.

The CRYSTAL code played an important role in demonstrating that band theory does not fail in the strongly interacting regime. The robust and efficient implementation of unrestricted Hartree-Fock theory helped us to identify and document the real problems with local approximations to electronics exchange and correlation.

I will review progress in the description of electronic interactions within the single particle framework and highlight the important role that Fock exchange is still playing in the description of strong interactions.