I want to calculate the berry curvature at the Dirac points in graphene with complex next nearest hopping (haldane model) in order to show that it is non-zero at the dirac points and use it to compute the Chern number. I've looked at different literature and know the equation for the berry curvature in terms of the wavefunction is
$\Omega = \nabla_k \times< \psi_{nk} | \nabla_k | \psi_{nk} > $
but I'm struggling to find the wavefunction for the haldane model to calculate this correctly.
