If there is a PhD or similar research project at a university, university of applied sciences, or certified research institution that is remunerated at the level of the reference rates and lasts around two years or longer, you can apply for this type of permit. Its advantage compared to the Settlement Permit - Special Cases of Gainful Employment is that it is possible to obtain the Red-White-Red Card Plus (the plus always stands for free access to the labour market) as a follow-up title after two years.

Info: All employed activities for which no work permit is required can be found in § 1 para 2 of the Act Governing the Employment of Foreign Nationals.