The phonon density of states of elemental Au, Cu, and Cu3Au with L12 chemical order were measured by inelastic neutron scattering and used to calculate the vibrational entropy of formation of the ordered compound from the elemental metals. A vibrational entropy of formation of (0.0660.03) kB /atom at 300 K was obtained, with the vibrational entropy of the ordered alloy being larger than that of...

Composition dependence of resistivity is studied in amorphous (Fe 100Àx Co x) 89Ày Zr 7 B 4 Cu y (0 x 50, y ¼ 0, 1) alloys. The two-current model proposed by Mott for crystalline materials is extended to a disordered amorphous system where s-d scattering is dominant in electron conduction. A rigid-band assumption is made due to the small atomic number difference between Fe and Co. Band structur...

Two-dimensional electron systems (2D ES}in a perpendicular magnetic field B display fascinating quantum oscillations. ' Examples of 2D ES's are electrons confined to interfaces in GaAs-Ga& „Al„As layered heterostructures and electrons at surfaces in Si metal-oxidesemiconductor field-effect transistors (MOSFET's). Earliest interest was in electron transport properties, the integer quantum hall e...

We prove Anderson localization in a disordered photonic crystal waveguide by measuring the ensembleaveraged extinction mean-free path, e, which is controlled by the dispersion in the photon density of states DOS of the photonic crystal waveguide. Except for the very low DOS case, where out-of-plane losses are non-negligible, e can be approximated to be the localization length . The extinction m...

We report the study of gold-SrTiO3 (STO)-gold memristors where the doping concentration in STO can be fine-tuned through electric field migration of oxygen vacancies. In this tunnel junction device, the evolution of the density of states (DOS) can be followed continuously across the metal-insulator transition (MIT). At very low dopant concentration, the junction displays characteristic signatur...

It has been demonstrated recently that the stoichiometry of rocksalt TaN can be tuned by N2 pressure and temperature, yielding material that ranges from highly conductive to insulating. Using density functional theory, we investigate the atomic and electronic structure and formation energy of defective TaN structures. The calculations predict that Ta and N vacancies form under N-rich and N-poor...

One of the most interesting aspects of amorphous semiconductor multilayers is their application in studying the interfaces between different a-Si:H based alloys, because of the great number of interfaces that a multilayer structure can contain. There are several magnitudes, such as the additional hydrogen content at interfaces [1,2] or the density of states (DOS) per interface [3-7] that can be...