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The momentum- and frequency-dependent T-matrix operator for the scattering of electromagnetic waves by a dielectric/conducting and para- or diamagnetic sphere is derived as a Mie-type series, and presented in a compact form emphasizing various symmetry properties, notably the unitarity identity. This result extends to magnetic properties one previously obtained for purely dielectric contrasts by other authors. Several situations useful to spatially-dispersive effective-medium approximations to one-body order are examined. Partial summation of the Mie series is achieved in the case of elastic scattering. [ABSTRACT FROM AUTHOR]

We show that a coherent picture of the dc conductivity of monolayer and bilayer graphene at finite electronic densities emerges upon considering that strong short-range potentials are the main source of scattering in these two systems. The origin of the strong short-range potentials may lie in adsorbed hydrocarbons at the surface of graphene. The equivalence among results based on the partial-wave description of scattering, the Lippmann-Schwinger equation, and the T-matrix approach is established. Scattering due to resonant impurities close to the neutrality point is investigated via a numerical computation of the Kubo formula using a kernel polynomial method. We find that relevant adsorbate species originate impurity bands in monolayer and bilayer graphene close to the Dirac point. In the midgap region, a plateau of minimum conductivity of about e2/h (per layer) is induced by the resonant disorder. In bilayer graphene, a large adsorbate concentration can develop an energy gap between midgap and high-energy states. As a consequence, the conductivity plateau is supressed near the edges and a "conductivity gap" takes place. Finally, a scattering formalism for electrons in biased bilayer graphene, taking into account the degeneracy of the spectrum, is developed and the dc conductivity of that system is studied. [ABSTRACT FROM AUTHOR]

A methodology is described to calculate the static effective permittivity for a two-dimensional multiphase lattice composed of dielectric and/or conducting circular cylinders. This methodology uses an accurate T-matrix method to determine the dipole moments of the cylinders immersed in a uniform electric field, and then computes the effective permittivity by relating the lattice to a macroscopic model. With this methodology, the multiple scattering solution for the infinite lattice is presented in a succinct matrix-vector notation and is valid for any lattice type. The static effective permittivity equation described in this work allows us to account for the effect of all mutual interactions between the cylinders. This methodology is used to calculate the static effective permittivity for a two-phase lattice of metallic inclusions. These results are compared with the Maxwell Garnett formula and another formula presented by Kharadly and Jackson. Three additional examples are presented including two-phase dielectric lattices, multiphase lattices, and clusters. The static effective permittivity in all three situations deviates from the Maxwell Garnett result at high-volume fractions, as expected. This deviation is the most obvious for the cluster lattice because of the significant mutual coupling between the cylinders, even at relatively low-volume fraction. [ABSTRACT FROM AUTHOR]