Search results for "upe"
showing 10 items of 7447 documents
Properties of the Phonon Gas in Ultrathin Membranes at Low Temperature
1998
We analyze heat conduction by phonons in ultrathin membranes by constructing a new theoreticalframework which implies a crossover from a bulk three-dimensional phonon distribution into a quasi-two-dimensional distribution when the temperature is lowered. We calculate the corresponding changesin the relevant thermodynamic quantities. At the end we make a comparison to experimental data.[S0031-9007(98)07273-1]
"Table 7" of "Search for supersymmetry in events with three leptons and missing transverse momentum in sqrt(s) = 7 TeV pp collisions with the ATLAS d…
2012
Missing transverse energy for events in the SR1 signal region for DATA and SM predictions.
"Table 1" of "Search for supersymmetry in events with three leptons and missing transverse momentum in sqrt(s) = 7 TeV pp collisions with the ATLAS d…
2012
Transverse momentum distribution for the first leading lepton for events in the SR1 signal region for DATA and SM predictions.
"Table 5" of "Search for supersymmetry in events with three leptons and missing transverse momentum in sqrt(s) = 7 TeV pp collisions with the ATLAS d…
2012
Transverse momentum distribution for the third leading lepton for events in the SR1 signal region for DATA and SM predictions.
"Table 3" of "Search for supersymmetry in events with three leptons and missing transverse momentum in sqrt(s) = 7 TeV pp collisions with the ATLAS d…
2012
Transverse momentum distribution for the second leading lepton for events in the SR1 signal region for DATA and SM predictions.
"Table 21" of "Search for supersymmetry in events with three leptons and missing transverse momentum in sqrt(s) = 7 TeV pp collisions with the ATLAS …
2012
The Systematic Uncertainty of the data (excluding the Monte Carlo) in signal region SR1 for the SUSY simplified model grid.
First-Principles Simulation of Substitutional Defects in Perovskites
2000
The results of supercell calculations of electronic structure and related properties of substitutional impurities in perovskite oxides KNbO3 and KTaO3 are discussed. For Fe impurities in KNbO3, the results obtained in the local density approximation (LDA) and in the LDA+U approach (that allows an ad hoc treatment of nonlocality in exchange-correlation) are compared, and different impurity charge configurations are discussed. The study of off-centre Li defects in incipient ferroelectric KTaO3 have been done by the appropriately parametrized Intermediate Neglect of Differential Overlap (INDO) method. The interaction energies of two off-centre impurities in different relative configurations ar…
Ab Initio Thermodynamics of Oxygen Vacancies and Zinc Interstitials in ZnO.
2015
ZnO is an important wide band gap semiconductor with potential application in various optoelectronic devices. In the current contribution, we explore the thermodynamics of oxygen vacancies and zinc interstitials in ZnO from first-principles phonon calculations. Formation enthalpies are evaluated using hybrid DFT calculations, and phonons are addressed using the PBE and the PBE+U functionals. The phonon contribution to the entropy is most dominant for oxygen vacancies, and their Gibbs formation energy increases when including phonons. Finally, inclusion of phonons decreases the Gibbs formation energy difference of the two defects and is therefore important when predicting their equilibrium c…
Semi-empirical supercell calculations for free- and bound-hole polarons in crystal
1997
Two different parametrizations of the semi-empirical method of the intermediate neglect of the differential overlap (INDO) are applied to the calculations of the small-radius hole polarons in the corundum crystal. The 80-atom supercell has been used for the study of the atomic and electronic structure of a free small-radius hole polaron (the self-trapped hole, STH) and a hole polaron bound by a Mg impurity (the so-called centre), respectively. Both parametrizations indicate that the two-site (quasi-molecular) configurations of both kinds of polaron have the lowest energy (which does not exclude the existence of one-site polarons also characterized by considerable relaxation energies). For c…
Pseudogap in high-temperature superconductors from realistic Fr\"ohlich and Coulomb interactions
2012
It has been recently shown that the competition between unscreened Coulomb and Fr\"{o}hlich electron-phonon interactions can be described in terms of a short-range spin exchange $J_p$ and an effective on-site interaction $\tilde{U}$ in the framework of the polaronic $t$-$J_p$-$\tilde{U}$ model. This model, that provides an explanation for high temperature superconductivity in terms of Bose-Einstein condensation (BEC) of small and light bipolarons, is now studied as a charged Bose-Fermi mixture. Within this approximation, we show that a gap between bipolaron and unpaired polaron bands results in a strong suppression of low-temperature spin susceptibility, specific heat and tunneling conducta…