Bandgaps, binding energies and charge transfer in density functional theory: meta-generalized gradient approximation and self-interaction correction

• Applicant: Professor Dr. Stephan Kümmel
• Subject Area: Theoretical Chemistry: Molecules, Materials, Surfaces ; Theoretical Condensed Matter Physics
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 457582427

Calculations and simulations using quantum mechanical density functional theory can predict the structure and properties of atoms, molecules and solids. They are therefore used in many areas of chemistry, physics and materials science. Such calculations make it possible, for example, to predict how molecules change on the surface of a solid during a catalytic process or how light is absorbed in a system and thus triggers the charge separation on which photovoltaics is based. The core idea of ​​density functional theory is to predict the properties of materials from the basic principles of quantum mechanics. The centerpiece of the theory is so-called exchange-correlation functional. This functional takes into account the quantum mechanical contribution of the electron-electron interaction to a system's total energy. The accuracy and predictive power, but also the computational expense of a density-functional theory calculation, depend decisively on this functional. In this project, approximations for the exchange-correlation energy are developed that aim to achieve high accuracy with the low computational effort. Particular attention is paid to the description of quantities such as the band gap, which are important for energy-converting materials such as solar cells or photocatalysts.

• DFG Programme: Research Grants