Moujaes, Elie A.Diery, W. A.
6页查看更多>>摘要：In this paper, we present a preliminary study to determine the electron-phonon (el-ph) coupling in Janus 1T monolayered PdSTe and PdSeTe within the rigid band approximation (RBA). Under the assumption that both electronic band structures and phonon dispersions remain intact, or suffer slight changes at most, the Fermi energy is manually shifted towards the conduction bands. Without spin-orbit coupling (SOC), these structures are predicted to be semiconductors with electronic bandgaps of 0.33 eV for PdSTe and 0.34 eV for PdSeTe and with an insignificant electron-phonon coupling. We find that minimal small Fermi energy shifts of the order of 35 meV and 65 meV applied to 1T PdSTe and PdSeTe respectively, are sufficient to produce non-zero values of A in both systems. These shifts could physically correspond to small electron doping of the materials, not exceeding 4%. Our calculations give that lambda = 1.77 and lambda = 0.5 for PdSTe and PdSeTe respectively. The corresponding lowest superconducting temperatures (T-c) register 0.28 K for PdSeTe and 28.19 K for PdSTe. We also demonstrate that the longitudinal optical and acoustical phonon modes may play a key role in the process of superconductivity of the doped materials. The above temperature of PdSTe is larger than those for 2D borophene, stanene, phosophorene and arsenene indicating that, in principle if the right dopant is found, lightly n-doped PdSTe could be promising in the area of 2D superconductors.
原文链接:
NSTL
Elsevier
Gal, JosephFriedlander, Lonia
6页查看更多>>摘要：Alternative bulk moduli for He, Ne, Ar, Xe and Kr, which differ from those reported in the literature, are presented. These alternative bulk moduli are based on the Gilvarry-Lindemann criterion, combined with a constraint demanding that the derived bulk moduli parameters will simultaneously fits the equations of state and the melting curves of these solid rare gasses. With increasing pressure, He, Ar, Xe and Kr exhibit a first order crystallographic phase transition from fcc to hcp structures. Ne is an exception and maintains the fcc phase up to 208 GPa. Good fits of the melting data are obtained by separately fitting each phase, allowing the extrapolation of the melting curves to higher pressures and temperatures. The anomalous linear behavior of the melting curve of Helium-4 is explained by assuming that the van der Waals attractive force should be added to the coulomb repulsion force when the distance between the two protons reduces under pressure. As the Gruneisen parameter gamma is directly related to the bulk moduli B and B ', it is concluded that the flattening of the melting curves in the hcp region is absolutely dependent on the correct determination of the bulk moduli.
原文链接:- NSTL
- Elsevier
Khomchenko, V. A.Das, M.Paixao, J. A.Silibin, M. V....
4页查看更多>>摘要：Magnetic properties of the phase-separated (antiferromagnetic + glassy) Bi0.85Ca0.15Fe0.6Mn0.4O3 multiferroic have been studied over a wide temperature range. It has been found that the material exhibits a metamagnetic transition (shifting toward smaller fields with decreasing temperature) which is accompanied by the magnetization jumps whose value (up to similar to 4 emu/g at T = 2 K) far exceeds that characteristic of the field-driven transformation from the cycloidal to the canted antiferromagnetic order in the pure BiFeO3. The metamagnetic behavior can be explained as originating from the spin-reorientation transition in the long rangeordered antiferromagnetic phase and involving magnetic moments from the glassy-like phase. The obtained results shed new light on the conditions favoring the coexistence of large switchable magnetization and spontaneous electric polarization in BiFeO3-based multiferroics.
原文链接:- NSTL
- Elsevier
Mayimele, M. A.Fru, J. N.Nyarige, J. S.Diale, M....
12页查看更多>>摘要：A comparative study was conducted between methylammonium lead tri-iodide (MAPbI3)/zinc oxide (ZnO) nanorods (NRs) on fluorine-doped tin oxide (FTO) and indium tin oxide (ITO) substrates for the first time. X-ray diffraction micrographs confirmed pure tetragonal MAPbI3 phase with I4/mcm space group and highly textured wurtzite hexagonal ZnO structure, having P63mc space group. Scanning electron micrographs revealed compact MAPbI3 grains on vertically aligned NRs. The average diameter of the NRs was 226 nm on ITO and 233 nm on FTO. Similarly, the average grain sizes of MAPbI3 were 280 nm and 210 nm on FTO/ZnO and ITO/ZnO, respectively. The bandgaps were respectively 3.05 and 3.18 eV for ITO/ZnO and FTO/ZnO, whereas that of FTO/ ZnO/MAPbI3 and FTO/ZnO/MAPbI3 were 1.580 and 1.584 eV, accordingly. Our findings indicate that FTO/ ZnO/MAPbI3/Au solar cells have a better performance than ITO/ZnO/MAPbI3/Au devices, and in-chamber annealing did not decompose MAPbI3 sequential vapor-deposited on ZnO nanorods.
原文链接:- NSTL
- Elsevier
Van Men, NguyenKhanh, Nguyen QuocLinh, Dang Khanh
4页查看更多>>摘要：We investigate zero-temperature plasmon modes in a double-layer bilayer graphene structure under a perpendicular electrostatic bias. The numerical results demonstrate that there exist two collective modes which are undamped in the long wavelength limit. The finite potential bias decreases remarkably the plasmon energy in a wide range of wave-vector and makes plasmon branches become Landau damped at a higher wave-vector as compared to unbiased case. We find that the dependence of plasmon dispersions on the system parameters such as the inter-layer separation and carrier density is similar in two cases with and without electrostatic bias.
原文链接:- NSTL
- Elsevier
Alotaibi, IbtessamAlshammari, Marzook S.Algessair, SajaMadkhali, N....
9页查看更多>>摘要：In this paper, sol-gel technique was used to prepare Gd-doped gamma-Fe2O3 nanoparticles and their heating efficiency for magnetic hyperthermia application was investigated. The obtained nanoparticles are characterized by several techniques. The structural properties are performed by X-ray diffraction (XRD), energy-dispersive X-ray spectrometer (EDAX) and X-ray Photoelectron Spectroscopy (XPS), while the morphology is investigated by Transmission electron microscopy (TEM). The magnetic properties and heating ability under an alternating magnetic field are performed by vibrating sample magnetometer (VSM) and magnetherm respectively. XRD, XPS and TEM results confirmed the maghemite (gamma-Fe2O3) phase, the presence of Gd ions and crystallinity. VSM hysteresis loops showed a negligible coercive field and remanence suggesting superparamagnetic behavior, which was also confirmed by Langevin method. Heating efficiency under an AC alternating magnetic field measurements showed that doped and un-doped samples display high heating ability and reached magnetic hyperthermia (42 degrees C) in relatively short times with shorter time (similar to 2 min) observed for gamma-Fe2O3 compared to 6 min for Gd (5%) doped gamma-Fe2O3 nanoparticles. The specific absorption rate (SAR) values decreased with increased concentration of Gd but remain considerable for all doped samples (up to 40W/g for Gd (5%)). The high crystallinity, superparamagnetic behavior and good SARs values make these nanoparticles a promising candidate for hyperthermia application.
原文链接:- NSTL
- Elsevier
Muraleedharan, SreepriyaAshok, Anuradha M.
8页查看更多>>摘要：ASnO(3) (A-Ca, Sr, Ba) nanostructured thin films were grown on corning glass substrates without seed layer via hydrothermal route. Structural and morphological characterisations confirmed phase purity, high crystallinity and uniform deposition of the films. Cost effective TCO, which has comparable optical and electrical properties of ITO has been the motivation of the current study. Bandgap (3.02-3.31 eV), transparency (>82%), conductivity (8.37 x 10(2) to 3.33 x 10(3) S/cm) and figure of merit values (0.8-6.04 x 10(-3) Omega(-1)) of ASnO(3)(ASO) films suggest that they could be useful for several optoelectronic applications. The materials developed in this work are made up of non-toxic as well as earth abundant elements and the thin films are deposited by simple chemical solution deposition method.
原文链接:- NSTL
- Elsevier
Li, LiangshengSun, WangLi, JingchunLi, Yunzhou...
7页查看更多>>摘要：The Terahertz laser modulating processes of monolayers of spheres have been theoretically investigated by using density functional and electromagnetic scattering method. The introduced free energy including static energy, electronic excitations and atomic vibrations was calculated by the density functional method. Thus, the heat capacity, the coefficient of thermal expansion and dielectric constant of materials could be obtained at various temperatures. When the high power THz laser passes through a CdTe sphere, the temperature traces can be changed and calculated by setting any laser waveforms. At a special frequency point, the real parts of permittivity could exhibit an oscillation with double modulation frequency. Furthermore, it was found that the resonance of monolayers could be dynamically tuned, and the oscillation behaviors of transmission are consistent with the modulation waveform. Finally, the resonant frequencies at Terahertz regions could be shifted to a given frequency by adjusting the lattice constants of monolayers.
原文链接:- NSTL
- Elsevier
Parvathi, L. T.Arunpandian, M.Sivaganesh, D.Nagarajan, E. R....
12页查看更多>>摘要：In this scenario, the Pd doped MnO2nanocatalysts were constructed by hydrothermal route. As-synthesized Pd loaded alpha-MnO2 nanocomposites were systematically characterized by various characterization techniques, respectively. The FESEM and TEM results reveal the surface morphology, the rose flower-like Pd was evenly decorated on the MnO2 surface. The elemental compositions of the presenting elements Pd, Mn and O are confirmed by XPS spectroscopic analysis. The photocatalytic activity of 2% Pd loaded alpha-MnO2 for crystal violet (CV) degradation was very high compared to immaculate alpha-MnO2 under visible light embellishment. Moreover, the radical trapping experiment substantiates that O2 center dot- and center dot OH plays a vital role in CV abatements. This work will provide new in-depth insights into other photocatalytic nanomaterials with potential applications in the field of environmental compensation. Besides, the electron density distributions analysis was carried out for this catalyst to explain the bond length value between the atoms.
原文链接:- NSTL
- Elsevier
