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arXiv 1204.0937cond-mat.mes-hall
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强关联量子点中含时电子输运:多探针开边界条件方法

Time-dependent electron transport through a strongly correlated quantum dot: multiple-probe open boundary conditions approach

A. Pertsova, M. Stamenova, S. Sanvito

摘要:

本文研究了强关联量子点中电子输运随时间的变化。与时间相关的电流是用多探针电池方法得到的,而绝热晶格密度泛函理论在Bethe局域密度近似的哈伯德模型描述的点的电子结构。我们发现,对于一定范围的电压的量子点可以驱动到一个动态的状态,其特征在于定期电流振荡。这是最近提出的库仑阻塞动力学图象的一种表现。此外,我们研究了电子-电子相互作用的各种近似如何影响库仑峰的线形和I-V特性。我们发现,在近似的交换相关电位的导数不连续的存在下,导致显着不同的结果相比,在更简单的Hartree水平的描述。特别地,在大偏压和大库仑相互作用强度下观察到I-V特性中的负微分电导(NDC)。我们证明了这种NDC起源于点中的电子-电子相互作用和电极的有限带宽的综合效应。

英文摘要:

We present a time-dependent study of electron transport through a strongly correlated quantum dot. The time-dependent current is obtained with the multiple-probe battery method, while adiabatic lattice density functional theory in the Bethe ansatz local-density approximation to the Hubbard model describes the dot electronic structure. We show that for a certain range of voltages the quantum dot can be driven into a dynamical state characterized by regular current oscillations. This is a manifestation of a recently proposed dynamical picture of Coulomb blockade. Furthermore, we investigate how the various approximations to the electron-electron interaction affect the line-shapes of the Coulomb peaks and the I-V characteristics. We show that the presence of the derivative discontinuity in the approximate exchange-correlation potential leads to significantly different results compared to those obtained at the simpler Hartree level of description. In particular, a negative differential conductance (NDC) in the I-V characteristics is observed at large bias voltages and large Coulomb interaction strengths. We demonstrate that such NDC originates from the combined effect of electron-electron interaction in the dot and the finite bandwidth of the electrodes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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