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We present a first-principles calculation of the quasiparticle electronic structure of ethylene adsorbed on the dimer reconstructed Si(001)-(2x1) surface. Within the GW approximation, the self-energy corrections for the adsorbate states are found to be about 1.5 eV larger than those for the states derived from bulk silicon. The calculated quasiparticle band structure is in excellent agreement with photoemission spectra. Finally, the effects of the quasiparticle corrections on the scanning tunneling microscope images of the adsorbed molecules are shown to be important as the lowering of the C2H4 energy levels within GW strongly reduces their tunneling probability. 相似文献
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Rignanese GM Detraux F Gonze X Bongiorno A Pasquarello A 《Physical review letters》2002,89(11):117601
Using density-functional theory, we compute the optical and static dielectric constants for a set of Zr silicates modeled by various SiO2 crystals, with Zr atoms substitutional to Si, and by an amorphous structure. We then derive a microscopic scheme that relates the dielectric constants to structural units centered on Si and Zr atoms through the definition of characteristic parameters. Applied to amorphous (ZrO2)(x)(SiO2)(1-x), these schemes describe the observed dependence of the dielectric constants on the Zr concentration and highlight the role of ZrO6 units. 相似文献
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Janine George David Waroquiers Davide Di Stefano Guido Petretto Gian‐Marco Rignanese Geoffroy Hautier 《Angewandte Chemie (International ed. in English)》2020,59(19):7569-7575
The Pauling rules have been used for decades to rationalise the crystal structures of ionic compounds. Despite their importance, there has been no statistical assessment of the performances of these five empirical rules so far. Here, we rigorously and automatically test all five Pauling rules for a large data set of around 5000 known oxides. We discuss each Pauling rule separately, stressing their limits and range of application in terms of chemistries and structures. We conclude that only 13 % of the oxides simultaneously satisfy the last four rules, indicating a much lower predictive power than expected. 相似文献
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Shaltaf R Rignanese GM Gonze X Giustino F Pasquarello A 《Physical review letters》2008,100(18):186401
We use many-body perturbation theory, the state-of-the-art method for band-gap calculations, to compute the band offsets at the Si/SiO2 interface. We examine the adequacy of the usual approximations in this context. We show that (i) the separate treatment of band structure and potential lineup contributions, the latter being evaluated within density-functional theory, is justified, (ii) most plasmon-pole models lead to inaccuracies in the absolute quasiparticle corrections, (iii) vertex corrections can be neglected, and (iv) eigenenergy self-consistency is adequate. Our theoretical offsets agree with the experimental ones within 0.3 eV. 相似文献
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Dr. Janine George Dr. David Waroquiers Dr. Davide Di Stefano Dr. Guido Petretto Prof. Dr. Gian-Marco Rignanese Prof. Dr. Geoffroy Hautier 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(19):7639-7645
The Pauling rules have been used for decades to rationalise the crystal structures of ionic compounds. Despite their importance, there has been no statistical assessment of the performances of these five empirical rules so far. Here, we rigorously and automatically test all five Pauling rules for a large data set of around 5000 known oxides. We discuss each Pauling rule separately, stressing their limits and range of application in terms of chemistries and structures. We conclude that only 13 % of the oxides simultaneously satisfy the last four rules, indicating a much lower predictive power than expected. 相似文献
6.
Connétable D Timoshevskii V Masenelli B Beille J Marcus J Barbara B Saitta AM Rignanese GM Mélinon P Yamanaka S Blase X 《Physical review letters》2003,91(24):247001
We present a joint experimental and theoretical study of the superconductivity in doped silicon clathrates. The critical temperature in Ba(8)@Si-46 is shown to strongly decrease with applied pressure. These results are corroborated by ab initio calculations using MacMillan's formulation of the BCS theory with the electron-phonon coupling constant lambda calculated from perturbative density functional theory. Further, the study of I(8)@Si-46 and of gedanken pure silicon diamond and clathrate phases doped within a rigid-band approach show that the superconductivity is an intrinsic property of the sp(3) silicon network. As a consequence, carbon clathrates are predicted to yield large critical temperatures with an effective electron-phonon interaction much larger than in C60. 相似文献
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Clemenza Massimiliano Bonesini Maurizio Carpinelli Massimo Cremonesi Oliviero Fiorini Ettore Gorini Giuseppe Hillier Adrian Ishida Katsu Menegolli Alessandro Mocchiutti Emiliano Oliva Piernicola Prata Marco Rendeli Marco Rignanese Luigi Pio Rossella Massimo Sipala Valeria Soldani Mattia Tortora Ludovico Vacchi Andrea Vallazza Erik 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1357-1363
Journal of Radioanalytical and Nuclear Chemistry - The implementation in the RIKEN-RAL negative muons facility of a new muon beamline monitoring and novel digital data acquisition system for gamma... 相似文献
8.
By means of ab initio simulations, we investigate the phonon band structure and electron-phonon coupling in small 4-A diameter nanotubes. We show that both the C(5,0) and C(3,3) tubes undergo above room temperature a Peierls transition mediated by an acoustical long wavelength and an optical q=2k(F) phonon, respectively. In the armchair geometry, we verify that the electron-phonon coupling parameter lambda originates mainly from phonons at q=2k(F) and is strongly enhanced when the diameter decreases. These results question the origin of superconductivity in small diameter nanotubes. 相似文献
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