Anisotropic off-normal incidence optical reflection from GaP (110) surfaces

This article contains a theoretical study for off-normal incidence surface induced optical anisotropy (SIOA). The discrete dipole approximation was used to calculate the off-normal incidence optical response of slabs. By means of the two slab approach those results were converted to semi-infinite reflectivities. The calculated ellipsometric parameter δΔ shows large variations near the Brewster angle, but only the p-polarized reflection has a clearly increased SIOA sensitivity. So experimentally a straightforward determination of ΔRp should be preferred. Advantages have to be sought in the optical observation of surface state related phenomena at subbandgap conditions

Exact solution of the optical response of thick slabs in the discrete dipole approach

The recently developed double cell technique, which describes the optical response of an arbitrary semi-infinite dielectric crystal taking into account internal field effects, is extended to include the response of thick slabs. The surface sensitivity of the first technique is fully retained. The implications of the internal field effects on the microscopy of these thick slabs are examined for three simple model systems. Further, we investigated under which conditions deviations from classical Fresnel-behaviour are to be expected and how important these corrections are

More efficient computation of the complex error function

Gautschi has developed an algorithm that calculates the value of the Faddeeva function w(z) for a given complex number z in the first quadrant, up to 10 significant digits. We show that by modifying the tuning of the algorithm and testing the relative rather than the absolute error we can improve the accuracy of this algorithm to 14 significant digits throughout almost the whole of the complex plane, as well as increase its speed significantly in most of the complex plane. The efficiency of the calculation is further enhanced by using a different approximation in the neighborhood of the origin, where the Gautschi algorithm becomes ineffective. Finally, we develop a criterion to test the reliability of the algorithm's results near the zeros of the function, which occur in the third and fourth quadrants

Reconstructions of the Ge(0 0 1) surface

We have performed dipole calculations of energies of the Ge(0 0 1) surface to compare the ground states of b(2 × 1), c(4 × 2), p(2 × 2) and p(4 × 1) symmetry dimer reconstructions. We have found that p(2 × 2) is the lowest energy reconstruction at zero temperature

Full microscopic treatment of the optical response of the Si(100)2x1 surface

The optical reflection from the Si(100) 2 × 1 surface has been calculated, using the discrete dipole model and local polarizabilities obtained from quantum mechanical cluster calculations. Results have been compared with experimental differential reflectance (Si) and optical anisotropy measurements (Ge)

The double cell technique:a discrete dipole approach towards surface optics

A local model based on the discrete dipole model has been developed in order to treat internal field effects at the surface of dielectric systems. The central part of the model is the double cell technique in which we match a freely chosen surface layer to the underlying bulk described by normal modes. We calculate the bulk and surface contributions to the anisotropic reflectance of the (1 1 0) surface of GaP obtaining results as good as the best delocalised treatments

Equivalence between the real time Feynman histories and the quantum shutter approaches for the "passage time" in tunneling

We show the equivalence of the functions $G_{\rm p}(t)$ and $|\Psi(d,t)|^2$ for the ``passage time'' in tunneling. The former, obtained within the framework of the real time Feynman histories approach to the tunneling time problem, using the Gell-Mann and Hartle's decoherence functional, and the latter involving an exact analytical solution to the time-dependent Schr\"{o}dinger equation for cutoff initial waves

Generalization of the coupled dipole method to periodic structures

We present a generalization of the coupled dipole method to the scattering of light by arbitrary periodic structures. This new formulation of the coupled dipole method relies on the same direct-space discretization scheme that is widely used to study the scattering of light by finite objects. Therefore, all the knowledge acquired previously for finite systems can be transposed to the study of periodic structures.Comment: 5 pages, 2 figures, and 1 tabl

X-Ray Resonant Exchange Scattering from 3d Transition Metal Surfaces

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