Quantum transport through a transverse quantum-dot shuttle
Quantum transport through a transverse quantum-dot shuttle
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通过横向量子点穿梭机的量子传输
DOI：
10.1103/physrevb.83.195308
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发表时间：
2011-05
影响因子：
3.7
通讯作者：
Han, Q. Z.
中科院分区：
文献类型：
--
作者：
Jiang, Z. T.;Yu, C. L.;Zhao, R. M.;Lue, J.;Han, Q. Z.
提出了一种横向量子点穿梭（T-QDS），它的振荡方向垂直于电子的传输方向，不同于通常的量子点穿梭的振荡方向平行于电子的传输方向.电自由度和力学自由度都用全量子力学方法处理。我们推导了修正的速率方程，并数值研究了T-QDS的量子特性。首先，作为比较，我们研究了经典T-QDS中电子占据几率和电流随时间的演化。结果表明，电流与T-QDS的振荡同相，呈现出随时间变化的振荡。然后，我们转而研究量子T-QDS的量子特性。与经典T-QDS不同的是，由于量子T-QDS空间位置的量子不确定性，没有观察到几率和电流的振荡。结果表明，量子T-QDS的量子化振荡引起的效应反映为量子点和引线之间隧穿率的重整化。值得注意的是，具有左引线和右引线的QD的两个隧穿速率以不同的方式取决于引线和QD的相对空间位置。这两个隧穿速率的相互作用最终决定了T-QDS的稳态电流。此外，我们还研究了温度的影响，这也可以通过重整化隧穿率来考虑。
Atransverse quantum-dot (QD) shuttle (T-QDS) is proposed where the QDoscillating direction is perpendicular to the electron transmission direction, different from the usual QD shuttle where the oscillating direction is parallel to the electron transmission direction. Both the electrical and mechanical degrees of freedom are dealt with by using the full quantum mechanical approaches. We derive the modified rate equations and numerically investigate the quantum properties of the T-QDS. First, as a comparison, we study the time-dependent evolutions of the electron-occupation probabilities and the currents flowing through the classical T-QDS. It is shown that the current shows the time-dependent oscillation in phase with the oscillation of the T-QDS. Then, we turn to study the quantum properties of the quantum T-QDS. Sharply different from the classical T-QDS, no oscillations of the probabilities and the current are observed due to the quantum uncertainty of the space position of the quantum T-QDS. It is demonstrated that the effects induced by the quantized oscillation of the quantum T-QDS are reflected as the renormalization of the tunneling rates between the QD and the leads. Notably, the two tunneling rates of the QD with the left and right leads depend on the relative space positions of the leads and the QD in different ways. It is the interplay of the two tunneling rates that eventually determines the stationary current of the T-QDS. Moreover, we study the influences induced by the temperature, which can also be considered via the renormalized tunneling rates.