Energy gaps in the failed high-Tc superconductor La1.875Ba0.125CuO4 Rui-Hua He, Kiyohisa Tanaka, Sung-Kwan Mo, Takao Sasagawa, Masaki Fujita, Tadashi Adachi, Norman Mannella, Kazuyoshi Yamada, Yoji Koike, Zahid Hussain, Zhi-Xun Shen Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA Advanced Light Source, La...

The momentum and temperature dependence of the lifetimes of acoustic phonons in the elemental superconductors lead and niobium were determined by resonant spin-echo spectroscopy with neutrons. In both elements, the superconducting energy gap extracted from these measurements was found to converge with sharp anomalies originating from Fermi-surface nesting (Kohn anomalies) at low temperatures. T...

A range of tuning methods, for enforcing approximate energy linearity through a system-by-system optimization of a range-separated hybrid functional, are assessed. For a series of atoms, the accuracy of the frontier orbital energies, ionization potentials, electron affinities, and orbital energy gaps is quantified, and particular attention is paid to the extent to which approximate energy linea...

This study investigates the electronic properties of finite-length armchair carbon nanotubes in an electric field (E) using a single-pi-band tight-binding model. Three different tip configurations are considered, namely, open ends with hydrogen terminations (H-terminations), one end capped with half of C60 fullerene and the other end open with H-terminations, and both ends capped with half of C...

The Lieb-Schultz-Mattis theorem is extended to generalized Heisenberg models related to unexceptional Lie algebras. It is shown that there are no energy gaps above the ground states for SO(4), Sp(2), and SU(4) Heisenberg models; but gaps are suspected to occur in SO(5) and SO(6) models. The nondegenerate ground state for these models is rigorously proven.

The collision-induced electronic energy transfer that occurs when I 2 in the E(0 g ϩ) ion-pair electronic state collides with ground electronic state I 2 has been investigated. We prepare I 2 in single rotational levels in vϭ0 of the E state using two-color double resonance laser excitation. The resulting emission spectrum shows that the nearby (⌬T e ϭϪ385 cm Ϫ1) D(0 u ϩ) electronic state is po...

the effects of halogens; fluorine, chlorine and bromine, on the stability and multiplicity of phenylcarbenes / silylenes/ germylenes structures are compared and contrasted at b3lyp/6-311++g**//b3lyp/6-31+g* level. the singlet-triplet energy gaps, δes-t , values for all the above speciesincrease through fluorinated up, δes-ts and δehomo–lumos support the stability of the singlet statesinspite of...

In this study, computational synthesis of carbon nanostructures' derivatives with TATB or 2,4,6-triamino-1,3,5- trinitrobenzene , which is an energetic substance in the temperature range of 300-400 K were evaluated by density functional theory method. In this regard, at the outset, the substances in the both sides of intended reactions for forming the desired products were optimized geometrical...

in this study, the adsorption of 4-hydroxy phenyl-azobenzene on the surface of (4, 0) zigzag open-end boron nitride nanotube (bnnt) has been investigated by quantum calculations. in order to find the preferred adsorption site, different positions and orientations were considered. the impacts of donor-acceptor electron delocalization on the structural and electronic properties and reactivity of ...