共查询到20条相似文献,搜索用时 109 毫秒
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固态六羰基钼的FT┐拉曼光谱研究李淑玲(地矿部岩矿技术研究所北京100037)任玲(北京理工大学化学与材料学院北京100081)FT┐RamanSpectraofSolidMo(CO)6LiShuling(InstituteofRockandMine... 相似文献
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铁掺杂的纳米SnO2的拉曼散射吴若(江西师范大学物理系南昌330027)左健(中国技术大学结构分析开放实验室合肥230026)RamanScateringofFe┐dopedNanoscaleSnO2WuRuo(DepartmentofPhysics... 相似文献
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金属原子簇化合物的拉曼光谱研究李淑玲(地矿部岩矿测试研究所北京100037)任玲(北京理工大学化工与材料学院北京100081)RamanSpectroscopicStudyofMetalclusterConpoundsLiShuling(Instit... 相似文献
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声子限制效应会引起本征硅纳米线拉曼光谱红移及不对称宽化,但研究发现其并非引起硅纳米线拉曼光谱改变的主要因素。研究表明,由于在拉曼光谱测量中,通常使用的入射激光功率都在5 mW以上,激光加热会导致很高的局部温度,从而引起拉曼光谱大幅度红移并对称宽化,这是硅纳米线拉曼光谱红移的主要影响因素。另外,激光功率很高时,由激光激发的载流子会与声子发生Fano型干涉,从而使硅纳米线拉曼光谱发生Fano型红移和不对称宽化。除此之外,对小直径本征硅纳米线,声子限制效应导致波矢选择定弛则弛豫,使不在布里渊区中心的声子也可以参与拉曼散射,因而其拉曼光谱中除常见的几个拉曼峰外还会出现新拉曼峰。 相似文献
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Motivated by the recent success of local electron tunneling into heavy-fermion materials, we study the local electronic structure around a single Kondo hole in an Anderson lattice model and the Fano interference pattern relevant to STM experiments. Within the Gutzwiller method, we find that an intragap bound state exists in the heavy Fermi liquid regime. The energy position of the intragap bound state is dependent on the on-site potential scattering strength in the conduction and f-orbital channels. Within the same method, we derive a new dI/dV formulation, which includes explicitly the renormalization effect due to the f-electron correlation. It is found that the Fano interference gives asymmetric coherent peaks separated by the hybridization gap. The intragap peak structure has a lorenzian shape, and the corresponding dI/dV intensity depends on the energy location of the bound state. 相似文献
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V. Ya. Aleshkin A. V. Antonov V. I. Gavrilenko B. N. Zvonkov D. V. Kozlov 《JETP Letters》2008,88(3):197-200
The impurity-photoconductivity spectrum is observed for strained quantum wells of the p-InGaAs/GaAs solid solution at T= 4.2 K. In addition to the broad photoconductivity band attributed to the transitions from the acceptor ground state to the continuum of the first size-quantization subband, the spectrum exhibits a peak due to the transitions from the ground state to the excited localized acceptor state, a band corresponding to the transitions to the resonance states associated with the second heavy-hole size-quantization subband, and a narrow photoconductivity peak (Fano resonance) in the spectral range corresponding to the optical-phonon energy. 相似文献
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Shailendra K. Saxena Rupnayan Borah Vivek Kumar Hari Mohan Rai Ravikiran Late V.G. Sathe Ashisha Kumar Pankaj R. Sagdeo Rajesh Kumar 《Journal of Raman spectroscopy : JRS》2016,47(3):283-288
A combined effect of doping (type and species) and size on Raman scattering from silicon (Si) nanowires (NWs) has been presented here to study interplay between quantum confinement and Fano effects. The SiNWs prepared from low doping Si wafers show only confinement effect, as evident from the asymmetry in the Raman line‐shape, irrespective of the doping type. On the other hand SiNWs prepared from wafer with high doping shows the presence of electron–phonon interaction in addition to the phonon confinement effect as revealed from the presence of asymmetry and antiresonence in the corresponding Raman spectra. This combined effect induces an extra asymmetry in the lower energy side of Raman peak for n‐type SiNWs whereas the asymmetry flips from lower energy side to the higher energy side of the Raman peak in p‐type SiNWs. Such an interplay can be represented by considering a general Fano‐Raman line‐shape equation to take care of the combined effect in SiNWs. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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《中国物理快报》2021,(5)
Detection of local strain at the nanometer scale with high sensitivity remains challenging. Here we report near-field infrared nano-imaging of local strains in bilayer graphene by probing strain-induced shifts of phonon frequency.As a non-polar crystal, intrinsic bilayer graphene possesses little infrared response at its transverse optical phonon frequency. The reported optical detection of local strain is enabled by applying a vertical electrical field that breaks the symmetry of the two graphene layers and introduces finite electrical dipole moment to graphene phonon. The activated phonon further interacts with continuum electronic transitions, and generates a strong Fano resonance. The resulted Fano resonance features a very sharp near-field infrared scattering peak, which leads to an extraordinary sensitivity of ~0.002% for the strain detection. Our results demonstrate the first nano-scale near-field Fano resonance, provide a new way to probe local strains with high sensitivity in non-polar crystals,and open exciting possibilities for studying strain-induced rich phenomena. 相似文献
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We analyze the relation between the density of states obtained from the energy derivative of the Friedel phase and that obtained from the Green's function of one- and quasi-one-dimensional wires with a double δ-potential. In the case of repulsive δ-potentials (in both one- and quasi-one-dimension), we show that the local Friedel sum rule is valid when a correction term is included. Various properties of the one-dimensional local density of states are also discussed. In the case of attractive δ-potentials in a quasi-one-dimensional wire, it is well known that the transmission probability may exhibit a Fano resonance (due to a zero-pole pair). In this case, we show that the local Friedel sum rule is valid provided that the tail of the quasibound state is taken into account by the integrated local density of states. In addition, we show that the density of states in a Fano resonance always has a Lorentz shape with peak position at the resonance energy regardless of the (Fano) asymmetry parameter. 相似文献
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氮化镓(GaN)是一种直接带隙Ⅲ~Ⅴ族半导体化合物,具有较宽的禁带宽度(Eg=3.4eV),较高的热稳定性,以及抗辐照等特性[1-4],是制备近紫外和蓝光光电子器件、高速微电子器件的理想材料.制备低维纳米结构,研究其物理性质既是理解低维量子现象的要求,也是未来纳米电子器件发展的需要.近年来,很多小组已经通过不同的方法成功地制备出GaN纳米棒、纳米线等一系列一维材料.这些方法包括碳纳米管辅助的方法[5]、电弧放电的方法[6]、激光刻蚀的方法[7]、升华法[8]、高温分解法以及化学气相沉积(CVD)[9-15].其中CVD方法以其制备过程简单,制备材料晶… 相似文献
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Shao-Hua Pan Zheng-Hao Chen Kui-Juan Jin Guo-Zhen Yang Yi Huang Tie-Nan Zhao 《Zeitschrift für Physik B Condensed Matter》1996,101(4):587-591
Fano’s theory is used to study the interaction between a continuum of Raman-active electronic intrasubband transitions and a discrete LO-phonon state in a semiconductor superlattice (SL). An explicit analytical expression of the asymmetry parameter q has been derived, which indicates the possibility of the occurence of Fano interference in intrasubband Raman scattering in suitably designed SL structures. The analytical expression clearly shows that q not only depends strongly on the SL parameters, but also depends sensitively on the exciting wavelength. The corresponding suitable design and preparation of SL samples and the performance of Raman experiments have also been carefully carried out for the first time. The theoretical calculations and experimental measurements show good qualitative and quantitative agreement. 相似文献
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It was proved by Pekeris(1) that the singly excited states of H- lie exactly at, or slightly above, the ground state of hydrogen. Using a theory of Fano,(2) these fictitious states will have a configuration interaction with the H- continuum. The strength of this configuration interaction is computed for the mixing of a 1s2p1P0 state with the H- continuum for different values of the fictitious binding energy of the 2p valence electron. In every case, the effect of the configuration interaction is to induce a rapid change of the phase shift of the continuum wave function by a quantity of π/2 over an energy range of a few times 0.01 eV, at an energy somewhat above the hydrogen ground state. The variation from π/2 to π is much slower. Such a swift change of the phase shift may be identified with the occurrence of a low-lying shape resonance. 相似文献
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This paper investigates the electronic transport properties in an
Aharonov--Bohm interferometer with a quantum dot coupling to left and
right electrodes. By employing cluster expansions, it transforms the equations of
motion of Green's functions into the corresponding
equation of motion of connected Green's functions, which provides a
natural and uniform truncation scheme. With this method under the
Lacroix's truncation approximation, it shows that the asymmetric line
shape of zero bias conductance manifests itself as the Fano effect,
and the Kondo effect has been observed in the narrow peak of
differential conductance curve of the system. Our numerical results
also show that the building of Fano state suppresses the amplitude
of Kondo resonance. 相似文献