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81.
82.
Aditya M. Vora 《Journal of Superconductivity and Novel Magnetism》2011,24(7):2065-2075
The theoretical investigations of the superconducting state parameters (SSP) viz. electron-phonon coupling strength λ, Coulomb pseudopotential μ ∗, transition temperature T C , isotope effect exponent α and effective interaction strength N O V of (Ni33Zr67)1−x M x (M=Ti,V,Co,Cu) ternary amorphous superconductors have been reported using Ashcroft’s empty core (EMC) model potential. Five different types of local field correction functions proposed by Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) are used in the present investigation to study the screening influence on the aforesaid properties. The T C obtained from Sarkar et al. (S) local field correction function are found in excellent agreement with available theoretical data. Quadratic T C equation has been proposed, which provides successfully the T C values of ternary amorphous alloys under consideration. Also, the present results are found to be in qualitative agreement with other such earlier reported data, which confirms the superconducting phase in the superconductors. 相似文献
83.
Aditya M. Vora 《Frontiers of Materials Science in China》2009,3(3):285-300
The vibrational dynamics of some Zr-based bulkmetallic glasses were studied at room temperature in terms of phonon eigen frequencies
of longitudinal and transverse modes employing three different approaches proposed by Hubbard-Beeby (HB), Takeno-Goda (TG)
and Bhatia-Singh (BS). The well recognized model potential is employed successfully to explain electron-ion interaction in
the metallic glass. The present findings of phonon dispersion curve are found to be in fair agreement with available theoretical
as well as experimental data. The thermodynamic properties obtained by the HB and TG approaches are found to be much lower
than those obtained by the BS approach. 相似文献
84.
High Open‐Circuit Voltages in Tin‐Rich Low‐Bandgap Perovskite‐Based Planar Heterojunction Photovoltaics 下载免费PDF全文
85.
Aditya M. Vora 《Frontiers of Materials Science in China》2007,1(4):366-378
The vibrational dynamics of three Ca-based non-crystalline alloys viz. Ca70Mg30, Ca70Zn30 and Ca60Al40 have been studied at room temperature in terms of the phonon eigen frequencies of longitudinal and transverse modes, employing
three theoretical formulations given by Hubbard-Beeby (HB), Takeno-Goda (TG) and Bhatia-Singh (BS). Five local field correction
functions viz. Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) are used for the first
time in the present investigation to study the screening influence on the aforesaid properties. The pseudo-alloy-atom (PAA)
model is applied for the first time instead of Vegard’s Law. Long wavelength limits of the phonon modes are used to investigate
the elastic and thermal properties of the system. The low temperature specific heat is also calculated from the elastic limit
of the phonon dispersion curves (PDCs). The present findings of the PDCs of Ca70Mg30 glass are found in fair agreement with available theoretical and experimental data. 相似文献
86.
Aditya M. Vora 《Journal of Superconductivity and Novel Magnetism》2007,20(5):387-392
The theoretical study of the superconducting state parameters (SSP) viz. electron–phonon coupling strength λ, Coulomb pseudopotential μ
*, transition temperature T
C
, isotope effect exponent α and effective interaction strength N
O
V of 5d-transition metals based binary alloys have been made extensively in the present work using a model potential for the
first time. A considerable influence of various exchange and correlation functions on λ and μ
* is found from the present study. The present results of the SSP are found in qualitative agreement with the available experimental
data wherever it exists. 相似文献
87.
The effect of uniaxial strain on the photocurrent spectrum of semiconducting single-wall carbon nanotubes is measured. The energy of the lowest-lying free electron transition is observed to shift with strain as predicted by a simple noninteracting model. The higher-order transitions also shift with strain, but being excitonic, their strain dependence differs from the predictions for the free carrier states. An anomalous photocurrent increase is also observed near the ground-state transition and is attributed to the formation of optically active defect states within the nanotube band gap. 相似文献
88.
Saxena AP Deepa M Joshi AG Bhandari S Srivastava AK 《ACS applied materials & interfaces》2011,3(4):1115-1126
Nanocomposite assemblies of poly(3,4-ethylenedioxythiophene) (PEDOT), embedded with (a) fluoro alkyl phosphate based ionic liquid functionalized graphene (ILFG) and (b) reduced graphene oxide (RGO) prepared from a modified Hummers' method, have been synthesized. Defect free graphene nanosheets within the size of a few nanometers were achieved in the PEDOT-ILFG nanocomposite. In contrast, structures comprising graphene oxide wrinkles interspersed with the amorphous polymer were obtained in the PEDOT-RGO nanocomposite. X-ray photoelectron spectroscopy showed that neat ILFG was considerably less oxidized as compared to the neat RGO, which ratified the superiority of the ionic liquid functionalization strategy over the conventional chemical approach, for exfoliating graphite. Substantially higher electrochemical activity, improved ionic/electronic conductivity, much faster switching rates, and an almost ballistic enhancement in the electrochromic coloration efficiency attained for the PEDOT-ILFG nanocomposite in comparison to PEDOT-RGO film were irrefutable proofs that demonstrated the ability of the ionic liquid to not only fortify the structure of graphene but also facilitate charge transport through the bulk of the film, by providing less impeded pathways. Since PEDOT-ILFG/-RGO nanocomposites of good uniformity have been achieved, this, to some extent, addresses the challenge associated with the processing of graphene based high performance materials for practical applications. 相似文献
89.
Vaddiraju S Mohite A Chin A Meyyappan M Sumanasekera G Alphenaar BW Sunkara MK 《Nano letters》2005,5(8):1625-1631
Indium nitride (InN) nanowire synthesis using indium (In) vapor transport in a dissociated ammonia environment (reactive vapor transport) is studied in detail to understand the nucleation and growth mechanisms involved with the so-called "self-catalysis" schemes. The results show that the nucleation of InN crystal occurs first on the substrate. Later, In droplets are formed on top of the InN crystals because of selective wetting of In onto InN crystals. Further growth via liquid-phase epitaxy through In droplets leads the growth in one dimension (1D), resulting in the formation of InN nanowires. The details about the nucleation and growth aspects within these self-catalysis schemes are rationalized further by demonstrating the growth of heteroepitaxially oriented nanowire arrays on single-crystal substrates and "tree-like" morphologies on a variety of substrates. However, the direct nitridation of In droplets using dissociated ammonia results in the spontaneous nucleation and basal growth of nanowires directly from the In melt surface, which is quite different from the above-mentioned nucleation mechanism with the reactive vapor transport case. The InN nanowires exhibit a band gap of 0.8 eV, whereas the mixed phase of InN and In(2)O(3) nanowires exhibit a peak at approximately 1.9 eV in addition to that at 0.8 eV. 相似文献
90.
Excitonic and free-carrier transitions in single-wall carbon nanotubes are distinguished using field-enhanced photocurrent spectroscopy. Electric field dissociation allows for the detection of bound-exciton states that otherwise would not contribute to the photocurrent. Excitonic states associated with both the ground-state semiconductor and the ground-state metallic nanotube transitions are resolved. The observation of a metallic excitonic state corroborates recent predictions of a symmetry gap existing in metallic nanotubes. 相似文献