My Community

Hello, I want to utilize VASP for computing the band alignment. I'm using the average electrostatic potential as a reference; however, for the bulk system, the average is zero. I suspect the potential is shifted. Are there any methods to compute the potential average for the bulk? Additionally, I have another question: there are two approaches - interface with vacuum and superlattice - both widely used for this type of calculation. Should I expect to obtain the same results using both techniques?

Hi,

Indeed, the average electrostatic potential (that means the Fourier coefficient corresponding to G=0) is set to zero. Anyway, the value of the average potential in the bulk is itself not important. What matter and have a physical meaning are differences, e.g., the difference between the average electrostatic potential and the Fermi energy. I have moved your post to "From Users for Users" such that other users may help you regarding your second question.