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[en] We report on the infrared spectroscopic studies of the normal-state electronic response of rare-earth ternary platinum germanide superconductor La_2Pt_3Ge_5. We analyzed the temperature-dependent optical conductivity spectra using the Drude-Lorentz oscillator model. We found that the two Drude responses with distinct scattering rates are required to explain the charge dynamics at 10 K while a single Drude mode could reproduce the far-infrared conductivity at higher temperatures. Our results indicated the two-band character of the electronic structure and highlighted the disparate temperature evolution of the electrodynamics of the two electronic states

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[en] Electron structure transformation under irreversible α→β polymorphous transitions under high pressure in molybdenum and tungsten digermanides is investigated by X-ray spectral and X-ray electron methods. It is shown that after α→WGe₂→βWGe₂ phase transition the hybride Wd+GeP-states grow above the Fermi level by increasing their energy and transfer to the free state zone. The change of charge state of nuclei after completion of α→β polymorphous transformations in MoGe₂ and WGe₂ is evaluated

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No abstract available

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[en] The mode of a novel SiGe-OI optical waveguide is analyzed, and its single-mode conditions are derived. The Ge content and structure parameters of SiGe-OI optical waveguides are respectively optimized. Under an operation wavelength of 1300 nm, the structures of SiGe-OI rib optical waveguides are built and analyzed with Optiwave software, and the optical field and transmission losses of the SiGe-OI rib optical waveguides are analyzed. The optimization results show that when the structure parameters H, h, W are respectively 500 nm, 250 nm, 500 nm and the Ge content is 5%, the total power loss of SiGe-OI rib waveguides is 0.3683 dB/cm considering the loss of radiation outside the waveguides and materials, which is less than the traditional value of 0.5 dB/cm. The analytical technique for SiGe-OI optical waveguides and structure parameters computed by this paper are proved to be accurate and computationally efficient compared with the beam propagation method (BPM) and the experimental results. (semiconductor devices)

[en] In this work, a novel three-layer SiGe strain relaxed buffer/strained Si_0.5Ge_0.5 layer stacking structure is systematically investigated. The novel three-layer graded SiGe strain relaxed buffer, whose Ge concentration increased from bottom to top by roughly 10% with an in situ annealing after each layer grown, can effectively constrain the threading dislocation in the strain relaxed buffer layer. Moreover, a chemical mechanical planarization process can be applied to the strain relaxed buffer to further improve its surface roughness. A high crystal quality and atomically smooth surface Si_0.5Ge_0.5 layer can be successfully realized on the novel chemical mechanical planarization-treated three-layer SiGe strain relaxed buffer. This strategy can attain at least 50 nm and 0.6% compressive strained Si_0.5Ge_0.5 layer and its quantification of the strain level is confirmed by utilizing the scanning moiré fringe imaging technique. It can be seen that this novel structure can provide a better mobility and larger width for the FinFET or nanowire SiGe channel device.