Dear All, I have three questions about the relation between the K-points and energy cutoff. The first one is : how many k points should I use in my theoretical calculation to get a good result in lattice constant and the converge of Emin especially for using DFT? The second one is : What is the relation in K-point and energy cutoff and is there any equation that can I use to describe this relation? How can I calculate this relation for graphene? I have used in my calculation GaAs to gain an accurate result. Regards.