We present an accurate study of the static-nucleus electronic energy band gap of solid molecular hydrogen at high pressure. The excitonic and quasiparticle gaps of the C2/c, Pc, Pbcn, and P63/m structures at pressures of 250, 300, and 350 GPa are calculated using the fixed-node diffusion quantum Monte Carlo (DMC) method. The difference between the mean-field and many-body band gaps at the same ...

An inelastic neutron scattering study of Cu2Te2O5X2 (X=Cl, Br) shows strong dispersive modes with large energy gaps persisting far above TN, notably in Cu2Te2O5Br2. The anomalous features: a coexisting unusually weak Goldstone-like mode observed in Cu2Te2O5Cl2 and the size of the energy gaps cannot be explained by existing theories, such as our mean-field or random-phase approximation. We argue...

The biradicaloid character of the ground-state structures of N2P2 rings is studied by using the high-level ab initio multiconfigurational CASPT2/CASSCF method. In order to obtain accurate descriptors, we combine two criteria: 1) singlet-triplet energy gaps and 2) relative values of the occupation numbers for bonding and antibonding orbitals associated with the radical sites. The singlet-triplet...

The operator H = d 4 dt4 + d dt p d dt + q with periodic coefficients p, q on the real line is considered. The spectrum of H is absolutely continuous and consists of intervals separated by gaps. The following statements are proved: 1) the endpoints of gaps are periodic or antiperiodic eigenvalues or branch points of the Lyapunov function, and moreover, their asymptotic behavior at high energy i...

Directional point-contact Andreev-reflection measurements in Ba(Fe(1-x)Co(x))2As2 single crystals (T(c) = 24.5 K) indicate the presence of two superconducting gaps with no line nodes on the Fermi surface. The point-contact Andreev-reflection spectra also feature additional structures related to the electron-boson interaction, from which the characteristic boson energy Ω(b)(T) is obtained, very ...

We propose and demonstrate a new field-induced quantum dot transistor that has a nanoscale dot-gate inside the gap of a split gate. Because of the novel structure and small dot size, strong oscillations in the drain current as a function of the gate bias were observed at a temperature up to 4.2 K or with a drain bias up to 5 mV. Temperature dependent study showed that the energy gaps in the dot...

In this study, reactions of the simple cycloalkynes with substituted Nitrile Oxides, by DFT method will be discussed. The investigation of the structural properties, theoretical thermodynamic and kinetic data, i.e., the activation free energies(DG*), the free energies changes of reaction(DrG) and rate constants of the reactions (k) in 298 K and effects of Electron-withdrawing and...

The structural and electronic properties in common-anion (GaSb) 1 /(InSb) 1 and common-cation (InAs) 1 /(InSb) 1 [111] ordered super-lattices have been determined using the local density total energy full potential linearized augmented plane wave method. The influence of the ordering direction, strain conditions and atomic substitution on the electronic properties of technological and experimen...

Energy gaps have been measured for the ferromagnetic quantum Hall effect states at ν = 1 and 3 in GaAs/Ga0.7Al0.3As heterojunctions as a function of Zeeman energy, which is reduced to zero by applying hydrostatic pressures of up to 20 kbar. At large Zeeman energy the gaps are consistent with spin-wave excitations. For a low-density sample the gap at ν = 1 decreases with increasing pressure and ...