Electronic structure of disordered graphene with Greenʼs function approach

► The Green functions play a big role in the calculation of the local density of states of the carbon nanostructures. ► We investigate their nature for the variously oriented and disclinated graphene-like surface. ► We investigate the case of a small perturbation generated by two heptagonal defects. ► We transform the given surface into a chain using the Haydock recursion method.