Hi all,
I have a little question when calculating the elastic constants of metals by VASP (IBRION=6). I heard from someone that the determination process includes moving single atom thus I need to make sure the cell is large enough to avoid an interaction between the moved atom in current cell and the moved atom in neighbour periodic cell. This leads to a huge increase in size of cell and thus computational work. However, when I check examples online, very small cells (even primitive cells) are widely used. I am very confused. Is there really any dimensional requirements for cell used for elastic constant calculation?
Thank you in advanced!