Density-functional theory (DFT) is the most widely used method to study the electronic structure of complex molecules, solids, and materials. Its use across chemistry, solid-state physics and materials science is a testament to its black-box nature and low cost. However, many important areas remain inaccessible to DFT simulations, including applications to strongly correlated materials and systems in electromagnetic fields. The topDFT project will deliver new conceptual approaches to design the next generation of density-functional methods. This will be achieved by pursuing three parallel strategies: i) Developing new strategies for the design of functionals ii) Implementing topological DFT, a new computational framework iii) Developing extended density-functional theories.
Techniques have been developed for learning about the behaviour of the exact density-functional from high level correlated calculations. These approaches have been significantly extended to treat open-shell systems and systems in the presence of external electromagnetic fields. A new framework for computation has been developed by combining techniques from topological electronic structure methods with DFT, allowing for the identification of correlation ‘hotspots’. This idea is chemically intuitive; electrons close together interact in a fundamentally different way to those far apart. The new computational approach is capable of recognising these hotspots, and adapting dynamically to them.
Extended-DFTs have been implemented and opened the way to routinely study systems in the presence of external electric and magnetic fields of arbitrary strength in a routine manner. These calculations have helped give insight into chemical reactivity in the presence of these fields, as well as their excited states and electron dynamics.
