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谐振子是量子力学中最基本也是十分典型和重要的问题,而在坐标表象中利用薛定谔方程的求解过程比较复杂.本文从两个无量纲的阶梯算符出发巧妙的推导出谐振子能量的本征值和本征矢,进而借用平移算符求解出谐振子的相干态.计算表明相干态表象的基矢是过完备的,同时在相干态中,坐标及其动量具有最小的不确定性. 相似文献
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利用紧束缚模型对二维三角周期格点中各能带的陈数分布进行研究.通过严格对角化方法得到体系能量本征值和对应的本征态,再利用Kubo公式计算出量子化的霍尔电导、态密度及各扩展态对应的陈数.在傅里叶变换下将哈密顿量转换到k空间从而得到体系的能谱分布.研究表明:次近邻格点之间的跳跃积分t'的不同取值影响体系各能带对应的陈数分布,计算得到当t'=1/2时体系三个能带从低到高对应的陈数分布为{-4,5,-1},t'=-1/2时其对应陈数分布变化为{2,-4,2},而t'=±1/4时对应的陈数分布都为{2,-1,-1}.同时发现:能谱帯隙的宽度和对应霍尔平台的宽度一致,并且k空间的能带越平坦,其对应的在霍尔电导跳跃处的态密度峰就越高越尖锐,而该处霍尔电导跳跃就越陡峭. 相似文献
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Nonlocal Andreev reflection and spin current in a three-terminal Aharonov--Bohm interferometer 下载免费PDF全文
This paper theoretically reports the nonlocal Andreev
reflection and spin current in a normal metal-ferromagnetic
metal-superconducting Aharonov--Bohm interferometer. It is found that the
electronic current and spin current are sensitive to systematic
parameters, such as the gate voltage of quantum dots and the
external magnetic flux. The electronic current in the normal metal
lead results from two competing processes: quasiparticle
transmission and nonlocal Andreev reflection. The appearance of zero
spin-up electronic current (or spin-down electronic current) signals
the existence of nonlocal Andreev reflection, and the presence
of zero electronic current results in the appearance of pure spin
current. 相似文献
4.
通过高温固相法合成了新型橙红色荧光粉Ba2 La8(1-x)Sm8x(SiO4)6O2,并对其光致发光特性进行了系统地研究.分析了Sm3掺杂浓度对发光强度的影响,结果显示其最佳掺杂摩尔浓度为3;,离子间能量传递机理为偶极-偶极相互作用.在15 ~250℃温度范围测试了荧光粉的发射光谱,结果表明合成的样品具有良好的温度稳定性.计算了荧光粉的色纯度和相关色温,制备样品的最高色纯度可达99.72;,相关色温低于1900 K.实验结果表明,近紫外光或蓝光可以有效激发此荧光粉.因此,该荧光粉在白光LED领域的具有潜在应用价值. 相似文献
5.
Phase coherence of the electron and hole in a ferromagnetic film in proximity with a superconductor 下载免费PDF全文
The scattering matrix approach between the clean and dirty limits is
developed for the study of tunneling spectra in a ferromagnetic film
in proximity to a superconductor. The minigap and the damped
oscillation from ``0" to ``π" state in tunneling conductance are
attributed to the phase coherence of the electrons and the
corresponding Andreev-reflected holes in the ferromagnetic film. The
calculated results provide a reasonable explanation for the behavior
observed in recent experiments. 相似文献
6.
将散射矩阵方法推广到超导双结系统,对正常金属/正常金属/超导结的隧道电导进行了研究.中间正常金属层中的电子和其Andreev反射空穴之间的相位相干性导致了隧道电导出现反常小能隙现象.综合考虑相干和顺序遂穿,计算结果理想的解释了最近Gupta等人在实验中观测到的反常小能隙现象. 相似文献
7.
Coexistence of ferromagnetism and superconductivity in normal mental/superconductor/ferromagnet structures 下载免费PDF全文
<正>We extend the Blonder,Tinkham and Klapwijk theory to the study of the inverse proximity effects in the normal mental/superconductor/ferromagnet structures.In the superconducting film,there are the gapless superconductivity and the spin-dependent density of states both within and without the energy gap.It indicates an appearance of the inverse-proximity-effect-induced ferromagnetism and a coexistence of ferromagnetism and superconductivity near the interface.The influence of exchange energy in the ferromagnet and barrier strength at the superconductor/ferromagnet interface on the inverse proximity effects is discussed. 相似文献
8.
Nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantum-dot ring 下载免费PDF全文
We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot(QD) ring,which is introduced as Rashba spin-orbital interaction to act locally on one component quantum dot.It is found that the electronic current and spin current are sensitive to the systematic parameters.The interdot spin-flip term does not play a leading role in causing electronic and spin currents.Otherwise the spin precessing term leads to shift of the peaks of the the spin-up and spin-down electronic currents in different directions and results in the spin current.Moreover,the spin-orbital interaction suppresses the nonlocal Andreev reflection,so we cannot obtain the pure spin current. 相似文献
9.
We extend the Blonder, Tinkham and Klapwijk (BTK) theory to the study
of the coexistence between ferromagnetism and s-wave
superconductivity in ferromagnet/superconductor (F/S) structures. It
is found that the ferromagnetism and s-wave superconductivity can
coexist near the F/S interface, which is induced by proximity
effects. On the F side, the density of states (DOS) exhibits some
superconducting-like properties, and it displays a damped oscillation
from `0' to `$\piE-mail: hlya7505@yahoo.com.cn /qk/85823A/200710/25696438.html proximity effects, `\pi' state,
Rashba spin--orbit coupling 7210, 7450 3/3/2007 12:00:00 AM We extend the Blonder, Tinkham and Klapwijk (BTK) theory to the study
of the coexistence between ferromagnetism and s-wave
superconductivity in ferromagnet/superconductor (F/S) structures. It
is found that the ferromagnetism and s-wave superconductivity can
coexist near the F/S interface, which is induced by proximity
effects. On the F side, the density of states (DOS) exhibits some
superconducting-like properties, and it displays a damped oscillation
from `0' to `$\pi$' states with increasing either the thickness of F
film or the exchange energy. We also study the influences of the
spin-polarized exchange splitting in the F and the spin-degeneracy by
Rashba spin--orbit coupling (RSOC) in the two-dimensional electron
gas (2DGE) on the proximity effects. It is shown that the case of
Rashba spin-degeneracy is very different from that of the
spin-polarized exchange splitting. http://cpb.iphy.ac.cn/CN/10.1088/1009-1963/16/10/042 https://cpb.iphy.ac.cn/CN/article/downloadArticleFile.do?attachType=PDF&id=108823 2007-10-08 ' states with increasing either the thickness of F
film or the exchange energy. We also study the influences of the
spin-polarized exchange splitting in the F and the spin-degeneracy by
Rashba spin--orbit coupling (RSOC) in the two-dimensional electron
gas (2DGE) on the proximity effects. It is shown that the case of
Rashba spin-degeneracy is very different from that of the
spin-polarized exchange splitting. 相似文献
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