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Abstract: Using the transfer matrix method, we have calculated the transmission spectra of symmetrical Fibonacci superlattices composed of positive and negative refractive index materials. In the ideal case where negative refractive index can be approximated as a constant in the frequency range considered, self-similarity behavior and perfect transmission peaks are observed in the spectra. While in the more realistic case where both ε and μ are negative, dispersive and modeled by the split-ring resonators (SRR) and cut-wires, both zero gap and Bragg reflection gaps are obtained. These transmission spectra are also compared with those of symmetrical Fibonacci superlattices with purely positive refractive index materials. [Copyright &y& Elsevier]

Abstract: The polaritonic band structures and transmission spectra of piezoelectric-modulated superlattices are investigated for a variety of supercell configurations. In the absence of a defect layer a polaritonic-like band gap exists and relative band gap can reach as large as 19% for superlattices made of LiNbO3. In the presence of a defect layer, the positions and number of defect modes can be controlled directly by the number of domains in a supercell, the widths of defect modes are determined by layer thickness difference between defect domain and the periodic domain. Such uniformly distributed in-gap modes make them ideal candidates for the potential multiband filters. [Copyright &y& Elsevier]

• The Bloch's band structures of a pair of interacting electrons are computed. • The band structures are classified as binding bands and unbinding continuum states. • Inter-site binding bands are obtained for both spin singlet and triplet states. • A scenario on possible Boson-Einstein condensation to the binding bands is discussed. We have applied the Bloch's theorem to a pair of interacting electrons in periodic simple one-dimensional lattice and two-dimensional square lattice with both intra-site and nearest neighbor inter-site interactions. The electronic structures can be classified as binding bands and unbinding continuum states of a pair of electrons. In addition to the usual intra-site binding band, we found the nearest-neighbor inter-site binding bands in both spin singlet and triplet states irrespective of interaction nature. The binding bands are either above or below the unbinding continuum states separated by gaps for a repulsive or attractive interaction potential. [ABSTRACT FROM AUTHOR]