scholarly journals Адсорбция атомов Ga и Cl и молекулы GaCl на карбиде кремния: модельный подход

2020 ◽  
Vol 62 (2) ◽  
pp. 298
Author(s):  
С.Ю. Давыдов ◽  
О.В. Посредник
Keyword(s):  
Adsorption Energy ◽  
Anderson Model ◽  
Ionic Model ◽  
Opposite Inequality ◽  
Ionic Contribution ◽  
Cl Atoms

Within the scope of the Haldane – Anderson model metallic and ionic contri-butions to the adsorption energy are calculated for the Ga and Cl atoms ad-sorbed on the C- and Si-faces of p- and n-SiC substrates. It is shown firstly that for all considered cases we obtain that ionic contribution is greater than metallic contribution. Secondly, in the case of adsorption on the p-SiC sub-strate value of the model of adsorption energy for Ga is greater than for Cl while in the case of adsorption on the n-SiC opposite inequality is realized. For the description of the GaCl adsorption on SiC substrate simple ionic model is put forward. Comparison with the results of other authors demonstrates valid-ity of the proposed models.

scholarly journals Адсорбция атомов бария на карбиде кремния

2020 ◽  
Vol 46 (1) ◽  
pp. 16
Author(s):  
С.Ю. Давыдов ◽  
О.В. Посредник
Keyword(s):  
Charge Transfer ◽  
Adsorption Energy ◽  
Anderson Model ◽  
Surface Molecule ◽  
Molecule Model

Adsorption of barium atoms on the C- and Si-faces of the 3C- 6H- and 4H-SiC polytypes is considered within the scope of the Haldane-Anderson model. Charge transfer from Ba atoms to the substrate is analyzed with the account of the band and local states of the adsorbed system. The ionic and metallic con-tributions to the adsorption energy are estimated. To improve some obtained results surface molecule model is used.

scholarly journals Адсорбция атомов I и VII групп на политипах карбида кремния

2020 ◽  
Vol 54 (11) ◽  
pp. 1197
Author(s):  
С.Ю. Давыдов ◽  
О.В. Посредник
Keyword(s):  
Charge Transfer ◽  
Adsorption Energy ◽  
Anderson Model ◽  
Alkali Metals ◽  
Metallic Parts

Within the scope of the Haldane-Anderson model the estimates of charge transfer and adsorption energy for alkali metals and halogens atoms on the С- and Si-faces of 3С-, 6Н- and 4Н-SiC polytypes are obtained. Band and local states contributions to the formation of adatom’s charge and ionic and metallic parts of the adsorption energy are clarified.

scholarly journals Адсорбция атомов II и VI групп на политипах карбида кремния

2021 ◽  
Vol 55 (4) ◽  
pp. 326
Author(s):  
С.Ю. Давыдов ◽  
О.В. Посредник
Keyword(s):  
Charge Transfer ◽  
Adsorption Energy ◽  
Anderson Model ◽  
Alkali Metals ◽  
Metallic Parts

Within the scope of the Haldane-Anderson model the estimates of charge transfer and adsorption energy for alkali metals and halogens atoms on the С- and Si-faces of 3С-, 6Н- and 4Н-SiC polytypes are obtained. Band and local states contributions to the formation of adatom’s charge and ionic and metallic parts of the adsorption energy are clarified.

Superconducting instability in the periodic Anderson model

1998 ◽  
Vol 78 (4) ◽  
pp. 365-374 ◽  
Author(s):  
A. N.Tahvildar-Zadeh, M. H. Hettler, M
Keyword(s):  
Anderson Model ◽  
Periodic Anderson Model

scholarly journals Giant enhancement of THz-frequency optical nonlinearity by phonon polariton in ionic crystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yao Lu ◽  
Qi Zhang ◽  
Qiang Wu ◽  
Zhigang Chen ◽  
Xueming Liu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Optical Nonlinearity ◽  
Ionic Crystals ◽  
Nonlinear Optical Susceptibility ◽  
Time Resolved ◽  
Light Coupling ◽  
Tremendous Progress ◽  
Fundamental Research ◽  
Ionic Contribution ◽  
Time Resolved Imaging

AbstractThe field of nonlinear optics has grown substantially in past decades, leading to tremendous progress in fundamental research and revolutionized applications. Traditionally, the optical nonlinearity for a light wave at frequencies beyond near-infrared is observed with very high peak intensity, as in most materials only the electronic nonlinearity dominates while ionic contribution is negligible. However, it was shown that the ionic contribution to nonlinearity can be much larger than the electronic one in microwave experiments. In the terahertz (THz) regime, phonon polariton may assist to substantially trigger the ionic nonlinearity of the crystals, so as to enhance even more the nonlinear optical susceptibility. Here, we experimentally demonstrate a giant second-order optical nonlinearity at THz frequency, orders of magnitude higher than that in the visible and microwave regimes. Different from previous work, the phonon-light coupling is achieved under a phase-matching setting, and the dynamic process of nonlinear THz generation is directly observed in a thin-film waveguide using a time-resolved imaging technique. Furthermore, a nonlinear modification to the Huang equations is proposed to explain the observed nonlinearity enhancement. This work brings about an effective approach to achieve high nonlinearity in ionic crystals, promising for applications in THz nonlinear technologies.

Flower-like tungsten-doped Fe–Co phosphides as efficient electrocatalysts for hydrogen evolution reaction

CrystEngComm ◽  
2021 ◽  
Author(s):  
Qian Zhang ◽  
Shuihua Tang ◽  
Lieha Shen ◽  
Weixiang Yang ◽  
Zhen Tang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Adsorption Energy ◽  
High Performance ◽  
Hydrogen Adsorption ◽  
Cost Effective

Developing cost-effective and high-performance electrocatalysts for hydrogen evolution reaction (HER) are imperative thanks to rapid increase of fuel-cell driven vehicles. Tungsten (W) possesses advantages of optimized hydrogen adsorption energy and...

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