I have some general questions about doing the structure relaxation of a thin film structure in VASP. I want to study the how the band structure evolves as we increase the number of layers of the material. The spin-orbit coupling (SOC) was included in the calculation, and I encounter the following question.
Should I turn the ISYM = 0 to also change the shape of the unit cell during the structure relaxation?
Should I include the SOC during the relaxation?
I saw some people doing this structure relaxation will fix the bottom layer of the slab by using the selective dynamic option, when should I use this technique?