We present an investigation of the dynamical response for a quantum wire structure with reservoirs. The capacitance, admittance, and the distribution of internal potential and charge density are calculated. Our numerical calculation for internal potential and charge density shows that the induced charge density is mainly distributed in transition regions between the reservoirs and the wire, and that once any quantum channel opens, the potential drop is very sharp and occurs in the transition regions. Small Friedel oscillations in the charge density as well as charge peaks are observed. We show in our model that in the reservoirs the characteristic potentials tend to unity or zero. The results of capacitance and emittance show the resonant peaks due to the opening of an additional channel, and the oscillations are related to the longitudinal states of the quantum wire. For capacitance, a steplike behavior appears as the number of open channels increase, but for emittance such steplike structure is not observed. Furthermore, we found that the emittance curves may lie either below or above capacitance, so the charge transmission may give positive or negative contributions to the emittance.

With the miniaturization of a solid down to nanometer scale, the elasticity, extensibility, Debye temperature, and specific heat capacity of the solid are no longer constant but change with variation of size. These quantities also change with the temperature of the measurement and the nature of the chemical bond involved. The mechanism behind the intriguing tunability and the interdependence of these quantities remain yet a high challenge. A set of analytical solutions is presented herewith showing that the observed trends could be reproduced by taking the fact of bond order deficiency into consideration. Agreement between predictions and observations clarifies that the shortened and strengthened surface bonds dictate intrinsically the observed tunability, yet atoms in the core interior remain as they are in the bulk. The thermally softening of a specimen arises from bond expansion and bond vibration due to the internal energy increases.

The correlation between the thermal stability and electroaffinity of a nanosolid has been explored from the perspective of surface and interface bond-order deficiency. It turns out that the coherency of an atom at the grain boundary and the portion of atoms in the skin of a nanosolid dominate the size dependence of critical temperatures ͑T C ͒ for phase transitions. The trapping potential well depression at the surface and interface not only shifts the valence density of state positively but also enlarges the electroaffinity that determines the strength of the bond. In particular, bond-nature alteration at the junction interface, or bond-nature evolution with the reduction of atomic coordination of III-or IV-A atoms, dominates the irregular T C change with the sizes of the embedded or the III-or IV-A bare nanosolids. Atoms in "superficial" or "interfacial" skins play the core role in dictating the size effect on the thermal stability and electroaffinity of a nanosolid whereas atoms in the core interior remain as they are in the bulk.

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We foresee applications and interesting possibilities of incorporating the photonic crystals concept into superconducting electronics. In this paper, we present interesting features of the computed lower band structure of a nondissipative superconductor-dielectric superlattice using the two-fluid model and the transcendental equation ͓Pochi Yeh, Optical Waves in Layered Media, Wiley Series in Pure and Applied Optics ͑Wiley, New York, 1988͔͒. The necessary conditions for approximating the complex conductivity by an imaginary conductivity is derived and the feasibility of achieving the conditions are discussed. The superlattice dispersion obtained is similar to that of the phonon-polariton dispersion in ionic crystal. We found a nonlinear temperature-dependent ''polariton gap'' and a low-frequency ͑plasma͒ gap, and suggested the existence of a photon-superelectron hybrid around the polariton gap. The polariton gap may be observed in an infraredmicrowave regime using a high-T c superconductor with sufficiently low normal-fluid relaxation time (Ϸ10 Ϫ15 s), and in an optical regime using lower penetration depth ͑Ϸ50 nm͒ and extremely low relaxation time (Ϸ10 Ϫ17 s). I. Introduction.Much work has been done on the computation of the band structures of electromagnetic waves propagating in two-and three-dimensional dielectric periodic structures since it was shown 1 that these periodic structures can be designed to produce the required band structures. The band structures explored were mainly fabricated from dielectric materials, 2-4 typically used in the semiconductor technology. Dielectric periodic structures can be designed to mold the light propagation in integrated semiconductor optoelectronics where electronic and optical signals coexist and transform between each other.Recently, combinations of various materials for the design of photonic crystals have been studied. Sigalas et al. 5 found wider photonic band gaps when dielectric constant and relative permeability have their maximum values in different materials and suggested using magnetically tuned ferrite materials. Electric-and magnetic-field-dependent materials like ferroelectrics, ferromagnets, and ferrimagnets were investigated in two-dimensional photonic crystals. 6 Frequencydependent dielectrics 7 and metallic 8 photonic crystals have been studied, too. We foresee novel applications and interesting possibilities of incorporating the photonic crystals concept into superconducting devices. From this motivation, in this paper we study the band structure of a onedimensional nondissipative superconductor-dielectric superlattice.We describe the electromagnetic response of a typical nonmagnetic superconductor using the two-fluid model 9,10 via the complex conductivity. The necessary and sufficient conditions that reduce the complex conductivity to imaginary conductivity are derived, since we are interested in a nondissipative superlattice. The superconductor satisfies the Gorter-Casimir relation. 11 The dielectric layer is characterized by a real dielectric consta...