I am new to solid state calculation. I have a question about the pseudopotential in terms of the relativistic effect. In solid-state calculations, ultrasoft pseudopotential using PBE functionals are widely used. I opened my ultrasoft pseudopotential file, I saw it says
'The Pseudo was generated with a Scalar-Relativistic Calculation'.
My question is, what is the definition of Scalar-Relativistic Calculation? I have a hard time finding the exact definition from a textbook. Are there any resources I can read about the scalar-relativistic effect?
Also, in order to generate the pseudopotential, the all-electron wavefunction needs to be calculated first, in ultrasoft pseudopotential, what kind of method do people use to calculate the all-electron wavefunction?
I really appreciate any comments on this. Thank you.