To obtain meaningful results from atomistic simulations of materials, the interatomic potentials must be capable of reproducing the thermodynamic properties of the system of interest. Pairwise potentials have known deficiencies that make them unsuitable for quantitative investigations of defective regions such as crack tips and free surfaces. Daw and Baskes [Phys. Rev. B 29, 6443 (1984)] have shown that including a local “volume” term for each atom gives the necessary many-body character without the severe computational dependence of explicit n-body potential terms. Using a similar approach, we have fit an interatomic potential to the Ni3Al alloy system. This potential can treat diatomic Ni2, diatomic Al2, fcc Ni, fcc Al and L12 Ni3Al on an equal footing. Details of the fitting procedure are presented, along with the calculation of some properties not included in the fit.

This paper presents a novel method for enhancing the electroluminescence (EL) efficiency of ten-period silicon-rich oxide (SRO)/SiO2 superlattice-based light-emitting diodes (LEDs). A hydrogen ion beam (HIB) was used to irradiate each SRO layer of the superlattices to increase the interfacial roughness on the nanoscale and the density of the Si nanocrystals (Si NCs). Fowler-Nordheim (F-N) tunneling was the major mechanism for injecting the carriers into the Si NCs. The barrier height of the F-N tunneling was lowered by forming a nano-roughened interface and the nonradiative Pb centers were passivated through the HIB treatment. Additionally, the reflectance of the LEDs was lowered because of the nano-roughened interface. These factors considerably increased the slope efficiency of EL and the maximum output power of the LEDs. The lighting efficiency increased by an order of magnitude, and the turn-on voltage decreased considerably. This study established an efficient approach for obtaining bright Si NC/SiO2 superlattice-based LEDs.

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Reactive sintering of elemental powders was used to form Y-doped Mg2Si (Y: 1000, 2000, 3000ppm) using a field-activated pressure assisted synthesis (FAPAS) method. XRD analysis, and the calculation of lattice constant (a) indicates that 1000ppm is the solid solubility of Y in Mg2Si. Sample doped with 2000ppm Y owns better performances, the absolute value of Seebeck Coefficient increases in the temperature of 288-580K and is higher than that of non-doped Mg2Si, and it got higher electric conductivity and higher power factor, which reaches up to 1.67 times of non-doped Mg2Si at 438K and 2.03 times of that of non-doped Mg2Si at about 408K. Meanwhile, the introduction of Y can decrease thermo-conductivity obviously, proving that the introduction of Y is favorable for both electrical and thermal properties.