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We propose a scheme for the effective polarization and manipulation of electron spin by using a quantum dot with both charge and spin bias. Using the equation of motion for Keldysh nonequilibrium Green function, we study the spin accumulation and polarization for the system. Through analytical analysis and a few numerical examples, it is demonstrated that fairly large spin accumulation and polarization can be produced due to the breakingsymmetry of the chemical potential for different electron spin in the leads. Moreover, the direction and the strength of the spin polarization can be conveniently controlled and tuned by varying the charge bias or the gate voltage. 相似文献
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自旋塞贝克效应是由(亚)铁磁体中的温度梯度引起自旋塞贝克电压信号的现象,目前已成为热自旋电子学研究的热点领域之一。本文采用反应磁控溅射工艺在Si衬底上沉积NiO薄膜,分别研究了溅射功率、氧氩比例、溅射气压、衬底温度对NiO薄膜微观结构和表面形貌的影响,实验中反应磁控溅射最适工艺条件为溅射功率110 W、氧氩比例0.15(O2 15 mL/min; Ar 100 mL/min)、溅射气压0.3 Pa、衬底温度400 ℃。研究了Si/NiO/Pt结构中温度梯度(温差)、磁场角度、NiO厚度变化和Pt厚度变化对自旋塞贝克电压的影响。结果表明,自旋塞贝克电压与温差呈简单的线性关系,温差越大测得的自旋塞贝克电压越高;磁场角度与自旋塞贝克电压之间满足余弦函数关系式,即在0°和180°时所得自旋塞贝克电压最大,90°和270°时为零;反铁磁性绝缘层NiO的厚度越大,所测得的自旋塞贝克电压信号越强;顺磁金属层Pt的厚度越大,自旋塞贝克电压信号越弱。 相似文献
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The derivation of Eq. (28) in the original paper [Chin. Phys. B 30 117101 (2021)] is corrected. 相似文献
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A new sulfate inorganic framework, {(C2H8N)9[Nd5(SO4)12]·2H2O}n(1) templated by organic amine, has been solvothermally synthesized and characterized by TGA, PXRD and single-crystal X-ray diffraction. Compound 1 crystalizes in monoclinic, space group C2/c with a = 20.570(5), b = 35.815(8), c = 10.106(2) , C318H72N9Nd5O50S12, Mr = 2315.73, V = 6765(3) , Z = 4, Dc = 2.274 g·cm-3, μ = 4.253 mm-1, F(000) = 4520, 2.52θ25°, λ(MoKα) = 0.71073 , T = 273(2) K, the final R = 0.0401, wR = 0.1022 and S = 1.042. X-ray diffraction analysis reveals that complex 1 possesses a 3D inorganic sulfate framework with large 20-membered ring(20 MR) and 10-membered ring(10 MR) channels constructed by two kinds of SBUs. Moreover, the UV-vis and luminescent properties of complex 1 were also investigated. 相似文献
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基于有限差分方法,研究周期梯度磁场调制下二维电子气的电子性质.结果表明:由于周期梯度磁场的存在,体系展现出丰富的电子能带结构.其子带的宽度随|ky|增大而不断变窄,|ky|越大势阱越深;由于在ky > 0和ky < 0两个区域的有效势能不一样,其能带结构在两个区域不一致且在ky > 0的区域中形成更多束缚态.通过改变磁条周期、磁条到2DEG的距离及磁化强度研究其对电子能带结构的影响. 相似文献
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色散和非线性效应对高斯脉冲综合影响的理论分析 总被引:4,自引:3,他引:1
从光孤子传输所满足的非线性薛定谔方程出发,采用单独分析和综合分析对比,分析了影响高斯脉冲传输的色散、非线性等因素,结果表明:二阶色散参量只会影响脉冲的幅值,对脉冲形状影响不大,而输入脉冲的啁啾则是使脉冲发生形变的主要原因;在啁啾、三阶色散和五阶非线性的共同作用下,它们对脉冲都会产生较大的影响,且存在相互影响和制约作用,在某一临界值,对脉冲存在着较高的压缩增益效应和"整形"作用.从理论上提出了改善高斯光脉冲在光纤中传输特性的解决方案,这对光纤孤子通信的实践过程具有一定的理论借鉴意义. 相似文献