In the last week, just before the Easter holidays, I visited Mainz for giving lectures on the density functional theory. It was an intensive course style, rather than a broad introduction over a semester, and I dealt with lots of practical aspects. I skipped all formal stuffs such as the Hohenberg-Kohm theorem and the Kohn-Sham formulation. I think these are basics that PhD students should know already (especially if one is planning to do theory). So, I started from the discussion on the choice of basis sets (e.g. plane wave, localized, augmented plane wave, etc.) and spent most of the time on the properties of the LAPW basis, which is the implementation that I use within the FLEUR code.

My motivation was to teach that an “optimal” choice of computation parameters is not really something that can only be learned only “by practice” (still required though) but something that naturally follows by understanding properties of the basis set. If one first encounters a DFT code that implements the FLAPW method, it is quite often that one is overwhelmed by so large number of parameters that has to be set. Well, the accuracy of the method comes at a cost of sophisticated parametrization. But if one understands the propertiees of the LAPW basis and its implementation, it becomes quite obvious that only a few paramters are really essential and the rest of them naturally follow.

I think my lecture sent quite well, and people seemed to be satisfied. Well, this has been only the first part, and the second part will continue in 2 weeks. My goal is for everyone to be able to calculate the anomalous Hall effect and spin-orbit torques at the end of the lecture series đź™‚