共查询到20条相似文献,搜索用时 15 毫秒
1.
The structural stability and electronic properties of (ZnO)n, (NiO)n, (ZnO)n/(NiO)n for n = (1 to 4) and 3D structures were studied using density functional theory. The geometrical optimisation of clusters implies that when the atoms in the cluster increase it leads to an increase in its stability. The stability drastically increases for the heterostructure of (ZnO)n/(NiO)n. The dipole moment of the clusters depends on the geometry of the cluster and it is found to be minimum for heterostructures representing more neutralised clusters. HOMO-LUMO energies, ionisation potential, electron affinity, chemical hardness, binding energies and vibrational analysis of different clusters are calculated and reported. The adsorption of CO on the different sites of nanoclusters are studied and discussed. 相似文献
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R. Acharya H. H. Aly H. A. Mavromatis K. Schilcher 《Zeitschrift für Physik A Hadrons and Nuclei》1968,211(4):324-328
The Weinberg sum rules have been successfully exploited to obtain the width of A1(1080) meson. Agreement with experiment is good. 相似文献
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Li JH Moss SC Zhang Y Mascarenhas A Pfeiffer LN West KW Ge WK Bai J 《Physical review letters》2003,91(10):106103
We report studies of (GaAs)(n)/(AlAs)(n) ultrashort-period superlattices using synchrotron x-ray scattering. In particular, we demonstrate that interfaces of these superlattices contain features on two different length scales: namely, random atomic mixture and ordered mesoscopic domains. Both features are asymmetric on the two interfaces (AlAs-on-GaAs and GaAs-on-AlAs) for n>2. Periodic compositional stacking faults, arising from the intrinsic nature of molecular-beam epitaxy, are found in the superlattices. In addition, the effect of growth interruption on the interfacial structure is discussed. The relevant scattering theory is developed to give excellent fits to the data. 相似文献
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《Superlattices and Microstructures》1993,13(1):115-123
The optical properties of (GaAs)n/(AlAs)m superlattices in the infra-red spectral region have been studied. The confinement of optical phonons has been observed in both GaAs and AlAs layers of superlattices under investigation. The superlattice modes caused by the coupling between LO phonons and collective intersubband excitations have been found in doped superlattices. Macroscopic and microscopic calculations have been used for the analysis of experimental results. Good agreement with experiment has been obtained. 相似文献
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Masato Okado 《Letters in Mathematical Physics》1991,22(1):39-43
A new series of solvable face models is presented. The Boltzmann weights are parametrized in terms of elliptic theta functions. This series generalizes the face models of type A
n
(1) introduced in [I]. 相似文献
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H. Rho J.‐R. Lim J. D. Song W. J. Choi Y. T. Lee 《Journal of Raman spectroscopy : JRS》2009,40(9):1178-1182
We report Raman scattering from (GaP)n/(InP)n (n = 1, 1.7, 2) short‐period superlattice (SPS) structures to study the effect of lateral composition modulation (LCM) on the behavior of optical phonons. Cross‐sectional transmission electron microscope images revealed that LCM was formed with complex pattern in the n = 1.7 and n = 2 samples grown at 490 °C. Interestingly, both the InP‐ and the GaP‐like longitudinal optical (LO) phonon energies increased systematically as the number of monolayers was increased from n = 1 to n = 2. A significant broadening of the phonon line shapes was also observed for the n = 1.7 and n = 2 samples. In contrast, for samples grown at 425 °C, both the increase of the LO phonon energies and the broadening of the phonon line shapes were observed only when n = 1.7. Our results demonstrate that the optical phonons in the (GaP)n/(InP)n SPS structures are significantly affected in the occurrence of LCM related to the growth temperature and the number of monolayers.Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Recently we used a method of stable analytic extrapolation to test whether strictly local duality between the asymptotic and the resonance region, which is believed to be valid in QCD, appears already at the present stage of QCD calculations. Probing the QCD ?-amplitude, we found a prominent bump structure in the resonance region, i.e. a rather direct evidence for the validity of local duality. In the present paper we confirm and extend this result by giving two further applications, theA 1-meson and the ?-meson. While we do not meet theA 1, as was to be expected since other sum rules can not separate it from the continuum, too, the extrapolation of the ?-amplitude leads to an enormous bump. Comparing this ?-bump with our ?-bump, we recover at least qualitatively the real proportions. 相似文献
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Local state probabilities for solvable restricted solid-on-solid models:A
n,D
n,D
n
(1)
, andA
n
(1)
The local state probabilities (LSPs) are exactly computed for four hierarchies of solvable lattice models. They are restricted solid-on-solid (RSOS) models whose local states and their adjacent conditions are specified by Dinkin diagrams of typesA
n,D
n,D
n
(1)
andA
n
(1)
. The LSPs are expressed in terms of modular functions characterized by branching identities among the theta functions. Their automorphic properties are used to study the critical behaviors. Some fine structures are found in the spectrum of the critical exponents. 相似文献
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Zhao HB Smith KJ Fan Y Lüpke G Bhattacharya A Bader SD Warusawithana M Zhai X Eckstein JN 《Physical review letters》2008,100(11):117208
Photoinduced magnetization dynamics is investigated in chemically ordered (LaMnO3)2n/(SrMnO3)n superlattices using the time-resolved magneto-optic Kerr effect. A monotonic frequency-field dependence is observed for the n=1 superlattice, indicating a single spin population consistent with a homogeneous hole distribution. In contrast, for n> or =2 superlattices, a large precession frequency is observed at low fields indicating the presence of an exchange torque in the dynamic regime. We attribute the emergence of exchange torque to the coupling between two spin populations-viscous and fast spins. 相似文献
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In this paper, we have conducted a first-principles study of the structural, electronic and optical properties of (CdS)n/(CdSe)n superlattices (where n is numbers of monolayers) in the wurtzite phase (B4), using the Full-Potential Linear Muffin-Tin Orbital (FP-LMTO) method within the Local Density Approximation (LDA) technique, in order to describe the exchange correlation energy. The calculated electronic properties indicate that all (CdS)n/(CdSe)n superlattices configurations, possess a semiconductor behavior with same energy gaps. We have seen more carefully and accurately that the different superlattices configurations have no effect on the electronic properties; in particular, we did not observe any dependence between the band gap behavior and the used layers. 相似文献
16.
Metal-insulator transition and its relation to magnetic structure in (LaMnO3)2n/(SrMnO3)n superlattices 总被引:1,自引:0,他引:1
Bhattacharya A May SJ te Velthuis SG Warusawithana M Zhai X Jiang B Zuo JM Fitzsimmons MR Bader SD Eckstein JN 《Physical review letters》2008,100(25):257203
Superlattices of (LaMnO3){2n}/(SrMnO3){n} (1or=3. Measurements of transport, magnetization, and polarized neutron reflectivity reveal that the ferromagnetism is relatively uniform in the metallic state, and is strongly modulated in the insulating state, being high in LaMnO3 and suppressed in SrMnO3. The modulation is consistent with a Mott transition driven by the proximity between the (LaMnO3)/(SrMnO3) interfaces. The insulating state for n>or=3 obeys variable range hopping at low temperatures. We suggest that this is due to states at the Fermi level that emerge at the (LaMnO3)/(SrMnO3) interfaces and are localized by disorder. 相似文献
17.
采用常规等离子体增强化学气相沉积工艺,以高H2稀释的SiH4作为反应气体源和PH3作为磷原子的掺杂剂,在p型(100)单晶硅((p)c-Si)衬底上, 成功地生长了施主掺杂型纳米硅膜((n)nc-Si:H),进而制备了(n)nc-Si:H/(p)c-Si异质结,并在230—420K温度范围内实验研究了该异质结的I-V特性.结果表明,(n)nc-Si:H/(p)c- Si异质结为一典型的突变异质结构,具有良好的温度稳定性和整流特性.正向偏压下
关键词:
(n)nc-Si:H/(p)c-Si异质结
能带模型
电流输运机构
温度特性 相似文献
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