There has been a search for alternative dielectrics with significantly increased dielectric constants, K, which increases in physical thickness proportional to K, and therefore would significantly reduce direct tunneling. However, increases in k to values of 15–25 in transition metal and rare earth oxides are generally accompanied by decreases in the conduction band offset energy with respect t...

The authors report on the electronic properties of individual molecules of two Mn12 derivatives chemically grafted on the functionalized Au 111 surface studied by means of ultrahigh vacuum scanning tunneling microscopy/spectroscopy at room temperature. Reproducible current-voltage curves were obtained from both Mn12 molecules, showing a well defined wide band gap. In agreement with the tunnelin...

A model for high temperature superconductors based on the idea of Cooper pairs comprised of electrons from different bands is studied. We propose that the two bands relevant for the cuprates are comprised of Cu dx2−y2, dz2 , planar O pσ, and apical O pz orbitals. Along the diagonal, kx = ky in the Brillouin zone, the two band Fermi surfaces may cross. We associate the optimal doping for the hig...

An important issue regarding DNA electrical conductivity is the electron (hole) transfer rate. Experiments have found that this transfer rate involves quantum mechanical tunneling for short distances and thermally activated hopping over large distances. The electron (or hole) tunneling probability through a molecule depends on the length of molecule L, as e(-beta(E)L), where the tunneling betaE...

in this paper, a photonic crystal waveguide with point defects and lattice constant perturbations of +5%, -5% are being investigated. firstly waveguide structures with constant and specific parameters are being studied and photonic band gap diagrams for te/tm modes are depicted; then pulse propagation in the frequencies available in the band gap are shown. after that, effects of parameters like...

Tunneling between a photoexcited p-type silicon tip and a gold surface is studied as a function of tip bias, tip-sample distance, and light intensity. In order to extend the range of application of future spin injection experiments, the measurements are carried out under nitrogen gas at room temperature. It is found that, while tunneling of valence band electrons is described by a standard proc...