Gap opening in single-layer graphene in the presence of periodic scalar and vector potentials within the continuum model

► We analysis the relationship of the degeneracy of the Dirac point and the symmetry of the Hamiltonian. ► We derive a gap equation at the Dirac point analytically with perturbation theory. ► Our gap equation shows a gap would be opened at the Dirac point with both electric and magnetic superlattice. ► Our gap equation is confirmed by the numerical calculation.