First-principles electronic structures were used to compute the lattice and elastic constants of single-crystal TiB and NbB and changes with Nb, Ti, Al and V solutes. The data were built into an interpolation formula for lattice and elastic constants of the quartenary (TiNbAlV)B with dilute Al and V concentrations. The lattice and elastic constants of borides in two Ti alloys containing Nb and ...

The lasing characteristics of a photonic crystal membrane heterostructure cavity that utilises a kagome type lattice is demonstrated. A heterostucture cavity is formed by interfacing two photonic crystals such that the dispersion maximum of the inner lattice falls within the photonic bandgap of the surrounding lattice. Feedback to slow Bloch modes allows for localisation of band edge modes and ...

X-ray diffraction provides one of the most important tools for examining the three-dimensional (3D) structure of biological macromolecules. The physics of diffraction requires that in order to resolve features of atomic structure it is necessary to employ radiation with a wavelength of the order of atomic spacing or smaller. Xrays have suitable wavelength, and interact with the electrons of the...

We describe a novel scheme based on evanescent guided-wave coupling for optically interfacing between conventional fiber-optic and planar photonic crystal devices such as waveguides and resonant cavities. By considering the band structure of bulk photonic crystal slabs, we analyze the k space properties of a linear defect waveguide and establish a set of design rules to ensure efficient evanesc...

In this work epitaxial growth of cobalt on CaF2(111), (110) and (001) surfaces has been extensively studied. It has been shown by atomic force microscopy that at selected growth conditions stand-alone faceted Co nanoparticles are formed on a fluorite surface. Grazing-incidence X-ray diffraction (GIXD) and reflection high-energy electron diffraction (RHEED) studies have revealed that the particl...

The theory of the crystal-field splitting, V,, of the J = I level of an ortho impurity in a parahydl-ogen matrix, due to the coupling of the rotational motion of the ortho molecule to the lattice vibrations, is developed taking due account of the quantum-crystal nature of the solid. Two contl-ibutions to V, are identified, both arising from the anisotropy in the lattice vibrations. One contribu...

The horizontal growth of nanowires (NWs) using the surface-directed vapor-liquid-solid (SVLS) process has been demonstrated for a number of semiconductors and shows the unique ability of eliminating post-growth alignment steps. However, the epitaxial relationship between horizontal NWs and their underlying surface has not been well understood, as it becomes more convoluted in systems with close...

Multibeam interference represents an approach for producing one-, two-, and three-dimensional periodic optical-intensity distributions with submicrometer features and periodicities. Accordingly, interference lithography (IL) has been used in a wide variety of applications, typically requiring additional lithographic steps to modify the periodic interference pattern and create integrated functio...

Bragg diffraction imaging enables the quality of synthetic single-crystal diamond substrates and their overgrown, mostly doped, diamond layers to be characterized. This is very important for improving diamond-based devices produced for X-ray optics and power electronics applications. The usual first step for this characterization is white-beam X-ray diffraction topography, which is a simple and...

We present results of computer simulations of crystal nucleation on a crystalline surface, in the Lennard-Jones model. Motivated by the pioneering work of Turnbull and Vonnegut [Ind. Eng. Chem. 44, 1292 (1952)], we investigate the effects of a mismatch between the surface lattice constant and that of the bulk nucleating crystal. We find that the nucleation rate is maximum close to, but not exac...