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Temperature-controllable spin-polarized current and spin polarization in a Rashba three-terminal double-quantum-dot device 下载免费PDF全文
We propose a Rashba three-terminal double-quantum-dot device to generate a spin-polarized current and manipulate the electron spin in each quantum dot by utilizing the temperature gradient instead of the electric bias voltage. This device possesses a nonresonant tunneling channel and two resonant tunneling channels. The Keldysh nonequilibrium Green's function techniques are employed to determinate the spin-polarized current flowing from the electrodes and the spin accumulation in each quantum dot. We find that their signs and magnitudes are well controllable by the gate voltage or the temperature gradient. This result is attributed to the change in the slope of the transmission probability at the Fermi levels in the low-temperature region. Importantly, an obviously pure spin current can be injected into or extracted from one of the three electrodes by properly choosing the temperature gradient and the gate voltages. Therefore, the device can be used as an ideal thermal generator to produce a pure spin current and manipulate the electron spin in the quantum dot. 相似文献
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We study the transport properties of electrons in a short homogeneous DNA molecule where thermal vibrations and twist fluctuations of the base molecules are considered. The nonlinear current-voltage curves can be derived by using the equivalent single-particle multichannel network. The voltage gap is sensitive to the strength of thermal vibrations and twist fluctuations of the base molecules. Our results are in good agreement with the recent finding of semiconducting behaviour in short poly(G)-poly(C) DNA oligomers. The present method can also be used to calculate the other molecular wires. 相似文献
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用不变量方法求含时谐振子的波函数 总被引:3,自引:1,他引:2
利用辅助方程从含量谐振子的哈密量出发得到了两个不变量,利用这两个不变量求得了系统薛定谔方程的解。 相似文献
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有源LC回路量子化后的波函数 总被引:8,自引:2,他引:6
从路径积分的方法出发,采用高斯型传播子,得出了有源LC回路量子化后的严格波函数,并讨论了电荷,电流,能量的零点起伏。 相似文献