The material system is described by the Hamiltonian and overlap matrice, with the Gaussian basis set.
At Gamma point in the reciprocal space, the upper triangle block and the lower triangle block in the Hamiltonian matrix are symmetric to each other.
What about other k point? At other k points in the reciprocal space, are the upper and lower triangle block in the Hamiltonian still symmetric to each other or not?
Would anyone give me some suggestions?
Thank you in advance.