共查询到19条相似文献,搜索用时 109 毫秒
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半导体中定域模,准定域模晶格振动的光谱研究 总被引:1,自引:0,他引:1
本文讨论了用光学方法研究杂质诱发定域化振动模的理论模型,分门别类地论述了半导体中杂质诱发的定域模、禁带模、共振模和准定域模晶格振动及非晶态半导体的晶格振动谱,给出了它们的综合结果。半导体中杂质诱发定域模已被人们广为研究,作者主要以自己的结果阐述了禁带模、共振模、准定域模和非晶态半导体振动谱研究在近年来取得的重要进展。除以较多篇幅研究各种定域化振动模的位置外,本文还从键—电荷模型出发讨论了杂质诱发振动吸收带的强度。 相似文献
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本文讨论了用光学方法研究杂质诱发定域化振动模的理论模型,分门别类地论述了半导体中杂质诱发的定域模、禁带模、共振模和准定域模晶格振动及非晶态半导体的晶格振动谱,给出了它们的综合结果。半导体中杂质诱发定域模已被人们广为研究,作者主要以自己的结果阐述了禁带模、共振模、准定域模和非晶态半导体振动谱研究在近年来取得的重要进展。除以较多篇幅研究各种定域化振动模的位置外,本文还从键—电荷模型出发讨论了杂质诱发振动吸收带的强度。 相似文献
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本文通过分析不同几何配置下的偏振拉曼光谱对非线性光学晶体的晶格振动模式进行了研究. 首先根据因子群分析,将晶体的振动模按晶体对称群的不可约表示进行分类,其次测量了晶体在10–1600 cm-1范围内,不同几何配置下的偏振拉曼光谱,并在此基础上指认了晶体的晶格振动模式. 300 cm-1以下的振动峰,归结为晶体的外振动,来自[BiO6],[ZnO4],[BO4]和[BO3]原子基团的平动和转动;300cm-1以上为晶体的内振动,主要与Bi-O,和Zn-O键振动有关. 晶体拉曼光谱中最高振动频率达到1407 cm-1,被指认为[BO3]三角形中B-O键的伸缩振动,体现了[BO3]基团中高的电子非局域化程度.
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2ZnOB2O6单晶')" href="#">Bi2ZnOB2O6单晶
偏振拉曼光谱
振动模式 相似文献
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基于晶格振动模受激电磁耦子散射过程的基本原理,对由LiTaO3(LT)晶体组成的太赫兹波参量振荡器(TPO)的输出调谐特性、增益和吸收损耗特性,以及基于硅棱镜阵列耦合装置的THz波输出特性等方面进行了详细的理论研究和分析.研究结果表明,基于LiTaO3晶体A1对称性晶格振动的特点以及自身优异的非线性光学特性,通过利用短波长抽运光、适当提高抽运能量以及缩短TPO谐振腔腔长等方法,完全可以实现LT-TPO的高性能运转,证明了LiTaO3晶体是一种性能优良的TPO工作介质.理论计算结果及方法为以后的LT-TPO实验工作提供了详实的理论依据和实验指导.
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非线性光学
THz辐射
3晶体')" href="#">LiTaO3晶体
电磁耦子 相似文献
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Infrared reflection and polarized Raman scattering spectra of cubic Td6 Bi4Ge3O12 single crystals were recorded, allowing the classification of the observed phonon modes into the different allowed symmetry. There is a good agreement with group theoretical predictions, since 25 phonon modes are localized, among the expected 27 ones. An assignment in terms of the GeO4 “tetrahedra” vibrations is tentatively given and discussed. 相似文献
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The localized vibrational modes around a bipolaron in cis-(CH)x are studied by using a two-dimensional extension of the SSH model that includes the bond-bending term. A number of additional modes have been found, compared with the results based on the standard SSH model The amplitudes of the two directions (x and y direction) are comparable for most of the modes as in the trans-(CH)x case. The number of localized modes and their frequencies depend not only on the coupling constant, but also on the bond-bending term and the parameter t1 in removing the degeneracy of the ground state. 相似文献
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The low temperature specific heat and thermal conductivity of (Cu50Zr50)94Al6 bulk metallic glass have been studied experimentally. A low temperature anomaly in the specific heat is observed in this alloy. It is also found that in addition to Debye oscillators, the localized vibration modes whose vibration density of state has a Gaussian distribution should be considered to explain the low temperature phonon specific heat anomaly. The phonon thermal conductivity dependence on temperature for the sample does not show apparent plateau characteristics as other glass materials do; however, the influence of the resonant scattering from the localized modes on the lattice thermal conductivity is prominent in the bulk metallic glass at low temperatures. 相似文献
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The localized modes in CaF2 due to the introduction of substitutional impurities have been investigated using the greens functions method. The weakening of the nearest neighbour interaction in all the alkaline earth fluorides, is estimated from the infrared absorption spectra on localized modes in these crystals. The splitting of the localized modes in CaF2, due to the presence of additional Sr2+ or Ba2+ impurities is estimated and satisfactory agreement exists between theory and experiment, within the limits of the simplifications in our calculations. 相似文献
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本文计算了简单立方铁磁体中由于磁性杂质的存在而形成的局域自旋波。其空间对称有s型模、p型模和dr型模三种。求出了各类局域模的波函数和自旋偏离的相角分布,其相应的能级与参量J′S′/JS的关系均由曲线表出。其次分析了在体心立方和面心立方铁磁体中可能出现的局域模的对称类型。我们指出,s型局域自旋波是最有可能实际观测到的。作为观测局域自旋波的样品的铁磁体,其居里点应随渗杂浓度的增加而上升。按照这一判据,我们举出一些可以试用的实验样品。最后,通过总自旋量子数的分析,一般地断定了辐射场不可能激
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V. A. Volodin M. D. Efremov V. V. Preobrazhenskii B. R. Semyagin V. V. Bolotov V. A. Sachkov E. A. Galaktionov A. V. Kretinin 《JETP Letters》2000,71(11):477-480
The phonon-plasmon interaction in tunneling GaAs n /AlAs m superlattices (m=5and 6≥n≥0.6 monolayers) was studied by Raman scattering spectroscopy. The interaction of optical phonons localized in GaAs and AlAs layers with quasi-three-dimensional plasmons strengthens as the thickness of GaAs quantum wells decreases and the electronic states in the superlattices become delocalized due to tunneling. It is assumed that the plasmons also interact with the TO-like phonon modes localized in quantum islands or in thin ruffled layers. 相似文献
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A new model is developed to describe the overtone spectra of polyatomic molecules containing XHn moieties. The infrared absorption is described as corresponding to excitation of localized modes of vibration rather than a set of symmetry allowed combinations of anharmonic normal modes. The possibility of assigning new bands in the more complex regions of the overtone spectra which involve combinations of both stretching and bending modes is examined and illustrated using the overtone spectrum of ammonia. The overtone spectrum of dichloromethane is recorded in the range λ = 9260 Å to λ = 5300 Å, and the CH overtone bands at 8850 Å, 7223 Å, and 6165 Å corresponding to the ΔvCH = 4, 5, and 6 overtones are identified. Specific features of these bands are discussed in detail in relation to the model. The common features and simplicity of the ΔvCH = 4 overtone bands of a series of halomethanes and ethanes are also interpreted in terms of the model. 相似文献