Effective Models for Optical Properties: A Study on 1D, 2D, and 3D Materials

In this thesis I employ effective Hamiltonian models to study the electronic structure of materials. With these models I study charge- and spin-injection induced by optical absorption processes, and current-injection induced by quantum interference processes between different orders of absorption. I study the optical response of narrow stripes (''nanoribbons'') of monolayer graphene, monolayers of tin atoms (''stanene''), and alloys of AlGaAs. First I focus on graphene nanoribbons with zigzag shapes along their lengths, along which strongly localized (''edge'') states exist at the Fermi level of undoped samples. I present results for different chemical potentials, showing that edge states are responsible for the main contribution to the optical response at low photon energies (Ph.D