Impurity-Induced Magnetization of Graphene

We present a model of impurity-induced magnetization of graphene assuming that the main source of graphene magnetization is related to impurity states with a localized spin. The analysis of solutions of the Schrödinger equation for electrons near the Dirac point has been performed using the model of massless fermions. For a single impurity, the solution of Schrödinger’s equation is a linear combination of Bessel functions. We found resonance energy levels of the non-magnetic impurity. The magnetic moment of impurity with a localized spin was accounted for the calculation of graphene magnetization using the Green’s function formalism. The spatial distribution of induced magnetization for a single impurity is obtained. The energy of resonance states was also calculated as a function of interaction. This energy is depending on the impurity potential and the coupling constant of interaction.

First principles study of IIIA atoms adsorbed on ZnO (0001) surface and the applications in optoelectronic devices

First principles method is used to study the adsorption behavior, formation energy and electronic structure of IIIA (B, Al, Ga, In) atoms adsorbed on Top, T4 and H3 sites of ZnO (0001) surface. The date shows that the formation energy of B, Al, Ga and In atoms adsorbed on Top site is highest, then followed by T4 site, and H3 is a more stable adsorption site. With the periodic increase of B, Al, Ga and In atoms, the formation energy of corresponding models decreases gradually, and the binding ability with O atoms also decreases gradually. The electronic structure of ZnO (0001) surface is sensitive to the adsorption sites. When these atoms are adsorbed on Top sites, the electronic structures of B-Top, Al-Top, Ga-Top and In-Top models have a little change compared with ZnO (0001) surface. However, when these atoms are adsorbed on T4 and H3 sites, the impurity states appear on the VBM, which narrowing the band gap of the corresponding models.

The impurity states in InGaAsP/InP coaxial double quantum well wires with the effects of electric and magnetic fields

The hydrogen donor impurity states are calculated in [Formula: see text] coaxial double quantum well wires by the plane wave method under the theoretical framework of effective mass envelope function approximation. The binding energies of impurity in [Formula: see text] state and [Formula: see text] state are obtained as the functions of impurity position, distance between the inner and outer quantum wires, magnetic and electric field strengths. Transition energies are calculated as the functions of impurity position, distance between the inner and outer quantum wires. The effects of quantum wire thickness and distance of quantum wires on impurity states are analyzed in detail. It is found that the effects of electric field and magnetic field on binding energy of [Formula: see text] state are different for impurity located at different positions.