On this second day of our spring school, the first ab initio solid state code is introduced: VASP, the Vienna Ab initio Simulation Package.
Having worked with this code for almost a full decade, some consider me an expert, and as such I had the dubious task of providing first contact with this code to our participants. Since all basic aspects and methods had already been introduced on the first day, I mainly focused on presenting the required input files and parameters, and showing how these should be tweaked for some standard type solid state calculations. Following this one-hour introduction, in which I apparently had not yet scared our participants too much, all participants turned up for the first hands-on session, where they got to play with the VASP program.
In the afternoon, we were delighted to welcome our first invited speaker, straight from the VASP-headquarters: Dr. Martijn Marsman. He introduced us to advanced features of VASP going beyond standard DFT. He showed the power (and limitations) of hybrid-functionals and introduced the quasi-particle approach of GW. We even went beyond GW with the Bethe-Salpeter equations (which include electron-hole interactions). Unfortunately, these much more accurate approaches are also much more expensive than standard DFT, but there is work being done on the implementation of a cubic scaling RPA implementation, which will provide a major step forward in the field of solid state science. Following this session, a second hands-on session took place where exercises linked to these more advanced topic were provided and eagerly tried by many of the more advanced participants.