Energy bands and gaps near an impurity

It has been suggested that in the neighborhood of a certain kind of defect in a crystal there is a bend in the electronic band. We confirm that this is indeed possible using the Kronig–Penney model. Our calculations also have implications for photonic crystals. - Highlights: • Energy bands can bend near an impurity in the host lattice. • We confirm possibility of energy band bending by using Kronig–Penney model. • The impurity can have profound effect on wave function structure.