Learning how the DFT codes work

I am a beginning PhD student studying topological materials and strongly-correlated systems, such as high Tc superconductivity. I am using density functional theory in my work. I am wondering what I need to know in order to master DFT calculations using vasp (and also QE). I currently have some level of understanding of the theoretical basis of DFT (the Kohn-Sham equations, the Hohenberg-Kohn theorem, the Levy-Lieb functional etc.), but I do not have a lot of understanding on the pseudo-potential formalism (e.g. PAW), and the algorithms used in VASP to calculate the electronic ground state (e.g. the blocked Davidson algorithm and the RMM-DIIS algorithms).

I am wondering if it pays to spend time trying to understand how the DFT code actually works and if so, what is the best way to do that. My principal goal is to do DFT calculations to understand topological systems and strongly-correlated material systems. This involves building tight-binding models etc.

• This might be a helpful start: mattermodeling.stackexchange.com/questions/7182/… Aug 31, 2022 at 23:54
• I also wrote some information about optimisation methods here: mattermodeling.stackexchange.com/questions/8795/… Sep 1, 2022 at 0:02
• That's great. Thanks. I haven't seen that answer. I spent a few days trying to understand PAW, both the blocked Davidson algorithm and the RMM-DIIS algorithms. I got some general idea, but it is still not clear to me since I don't have a background in numerical linear algebra.
– user5405
Sep 1, 2022 at 0:05
• If you'd like to post a more specific question (e.g. "how does density mixing work?") you'd probably get more answers (I could answer that one, for example). Sep 1, 2022 at 0:25
• Some information on the Davidson method: mattermodeling.stackexchange.com/questions/6563/… Sep 1, 2022 at 0:26