Treatment of Magnetic Fields in Density-Functional Theory

Abstract

Magnetic properties are an important application area in quantum chemistry. However, for the most widely used method in electronic structure calculations, density-functional theory, it is still not understood how to rigorously include the magnetic field into the exchange--correlation functional. This work contributes to and further develops magnetic-field density-functional theory (BDFT), which is an alternative to, but less well-known, than current density-functional theory (CDFT). A major focus is to investigate the importance to introduce a magnetic-field dependence into density functional approximations (DFAs) to improve the computation of magnetic properties. The main conclusion is that the full benefit of a field dependence can only be realized if simultaneously the self-consistent density of present DFAs is improved. The investigations and results of this work provide valuable information both for further theoretical developments of BDFT and for the proper inclusion of magnetic field effects into DFAs, which will allow more accurate results for density-functional calculations involving magnetic fields.