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41.
We theoretically investigate the effect of the interdot Coulomb repulsion on Kondo resonances in the series-coupled double quantum dot coupled to two ferromagnetic leads. The Hamiltonian of our system is solved by means of the slave-boson mean-field approximation, and the variation of the density of states, the transmission probability, the occupation number, and the Kondo temperature with the interdot Coulomb repulsion are discussed in the Kondo regime. The density of states is calculated for various interdot Coulomb repulsions with both parallel and antiparallel lead-polarization alignments. Our results reveal that the interdot Coulomb repulsion greatly influences the physical property of this system, and relevant underlying physics of this system is discussed.  相似文献   
42.
研究了快速C60 离子团在固体中穿行时的库仑爆炸过程 .假定离子团中离子之间位置矢量的取向是随机的 ,并且采用球壳模型描述C60 离子团的结构 .借助于线性介电响应理论和等离子 极点近似介电函数 ,推导出C60 离子团自能的解析表达式 .通过数值求解描述离子团半径变化的运动方程 ,可以发现自能中的“尾效应”可以降低C60 离子团的库仑爆炸速度 ,甚至可以稳定C60 离子团的结构  相似文献   
43.
半导体量子电子和光电子器件   总被引:6,自引:0,他引:6  
傅英  徐文兰  陆卫 《物理学进展》2001,21(3):255-277
本阐述了半导体异质结构电子的量子特性,如电子波输运,库仑阻塞效应等,介绍了几种新颖,典型的量子电子器件和量子光电子器件的物理模型和基本原理,这些器件包括了单电子晶体管,共振隧穿二极管,高电子迁移率晶体管,δ掺杂场效应晶体管,量子点元胞自动机,量子阱红外探测器,埋沟异质结半导体激光器,量子级联激光器等,给出了作在半导体量子器件物理方面的最新研究结果。  相似文献   
44.
The metal-oxide-semiconductor (MOS) field effect transistor (FET) using ‘oxidized μ c-Si/ultrathin oxide’ gate structure was studied. It was found that this structure shows negative differential resistance behavior, which can be explained by the Coulomb blockade effect of trapped carriers and immediate tunneling into and tunneling out with gate bias variation. The requirements for the device with this structure showing negative differential resistance behavior are based on very weak resistive coupling between floating gate and channel. They are the thinness of the tunnel oxide film, the thickness ratio of the upper oxidized film and the tunnel oxide, and the channel threshold voltage. MOSFET with this gate structure is proposed as a new negative differential resistance device.  相似文献   
45.
Making use of the relativistic BBGKY technique,the relativistic generalization of Landau collision integral is botained.Furthermore,we calculate the relativistic hydrodynamic modes up to the second order in the hydrodynamic wave number.Combining Resibois‘ method,we present the first principle formula of the relativistic heat conductivity of Coulumb electronic plasmas for low-order corrections.  相似文献   
46.
This is a general and exact study of multiple Hamiltonian walks (HAW) filling the two-dimensional (2D) Manhattan lattice. We generalize the original exact solution for a single HAW by Kasteleyn to a system ofmultiple closed walks, aimed at modeling a polymer melt. In 2D, two basic nonequivalent topological situations are distinguished. (1) the Hamiltonian loops are allrooted andcontractible to a point:adjacent one to another, and, on a torus,homotopic to zero. (2) the loops can encircle one another and, on a torus, canwind around it. Forcase 1, the grand canonical partition function and multiple correlation functions are calculated exactly as those of multiple rooted spanningtrees or of a massive 2Dfree field, critical at zero mass (zero fugacity). The conformally invariant continuum limit on a Manhattantorus is studied in detail. The melt entropy is calculated exactly. We also consider the relevant effect of free boundary conditions. The number of single HAWs on Manhattan lattices with other perimeter shapes (rectangular, Kagomé, triangular, and arbitrary) is studied and related to the spectral theory of the Dirichlet Laplacian. This allows the calculation of exact shape-dependent configuration exponents y. An exact surface critical exponent is obtained. Forcase 2, nested and winding Hamiltonian circuits are allowed. An exact equivalence to thecritical Q-state Potts model exists, whereQ 1/2 is the walk fugacity. The Hamiltonian system is then always critical (forQ<-4). The exact critical exponents, in infinite numbers, are universal and identical to those of theO(n=Q 1/2) model in its low-temperature phase, i.e. are those of dense polymers. The exact critical partition functions on the torus are given from conformai invariance theory. These models 1 and 2 yield the two first exactly solved models of polymer melts.  相似文献   
47.
 在量子理论的框架内,利用含强激光场的二级相对论修正的运动方程,采用直接数值解法,着重研究了强激光场和Debye屏蔽库仑场下荷电粒子的碰撞截面及其与激光脉冲波形、频率、强度和屏蔽参数等的关系。  相似文献   
48.
Eighteen previously unknown γ-ray transitions were identified in the T z = - 1/2 nucleus 51Fe following the fusion-evaporation reaction 32S(28Si,2α1n)51Fe. The level scheme reaches the fully aligned I π = 27/2- terminating state of the five holes in the f 7/2 shell. The 17/2- state was found to be isomeric, and the lifetime was measured to be 2.87 ns. The mirror symmetry of 51Fe and 51Mn is discussed, and the level scheme of 51Fe is compared to shell-model calculations. Received: 20 July 2000 / Accepted: 1 August 2000  相似文献   
49.
I discuss our replication of the wire-torsion experiments that Charles Augustin Coulomb (1736–1806) reported in a session of the Paris Académie des Sciences in 1784. I first explain the nature and purpose of the replication method and then apply it to an analysis of Coulomb’s experiments. I conclude by placing Coulomb’s presentation of his memoir into its specific historical contest.  相似文献   
50.
Ajay Sharma  Meenu Singh  Raj Mittal 《Pramana》2006,66(6):1111-1117
Alignment of photon-induced L3 vacancies is studied in rare earth and highZ elements at energies of experimental interest, near thresholds to 60 keV, under nonrelativistic dipole approximation. Numerical calculations of the matrix element are undertaken to produce theoretical data for comparison with the experimental findings. The A2 values being s>0.1 at photoelectron energies <20 keV are certainly higher than 5–8% uncertainties quoted in experimental results. Present findings are from a very basic model, hydrogen-like and can further be treated as reference to observe the impact of screening, relativistic, multipole and retardation corrections to the model  相似文献   
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