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arXiv 0808.3370cond-mat.mes-hall
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介观导体中的元电荷转移过程

Elementary Charge Transfer Processes in Mesoscopic Conductors

Mihajlo Vanevic, Yuli V. Nazarov, Wolfgang Belzig

摘要:

我们确定了在含时电压驱动下量子导体中的电荷转移统计,并确定了基本的输运过程。在零温度下,发生单向和双向单电荷转移。单向过程涉及由于过量的直流偏置电压而从源极端子注入的电子。双向过程涉及由随时间变化的偏压产生的电子-空穴对。这种解释是进一步支持的电荷转移统计在多端分束器的几何形状,其中注入的电子和空穴可以被划分到不同的传出终端。基本过程的概率可以通过噪声测量来探测:单向过程设置直流噪声电平,而双向过程则产生过量噪声。对于交流电压驱动,噪声随着驱动幅度的增加而振荡。将噪声分解为基本过程的贡献确定了这些振荡的起源:每个周期产生的电子-空穴对的数量随着振幅的增加而增加。不同的时间依赖的电压的噪声分解成基本过程进行了研究。该方法也适用于有限温度下高阶电流互感器的系统计算。我们得到了电流噪声功率和第三累积量的存在下,时间依赖的电压驱动。有限温度下的电荷转移统计可以解释为多次电荷转移,其概率取决于能量和温度。

英文摘要:

We determine charge transfer statistics in a quantum conductor driven by a time-dependent voltage and identify the elementary transport processes. At zero temperature unidirectional and bidirectional single charge transfers occur. The unidirectional processes involve electrons injected from the source terminal due to excess dc bias voltage. The bidirectional processes involve electron-hole pairs created by time-dependent voltage bias. This interpretation is further supported by the charge transfer statistics in a multiterminal beam splitter geometry in which injected electrons and holes can be partitioned into different outgoing terminals. The probabilities of elementary processes can be probed by noise measurements: the unidirectional processes set the dc noise level while bidirectional ones give rise to the excess noise. For ac voltage drive, the noise oscillates with increasing the driving amplitude. The decomposition of the noise into the contributions of elementary processes identifies the origin of these oscillations: the number of electron-hole pairs generated per cycle increases with increasing the amplitude. The decomposition of the noise into elementary processes is studied for different time-dependent voltages. The method we use is also suitable for systematic calculation of higher-order current correlators at finite temperature. We obtain current noise power and the third cumulant in the presence of time-dependent voltage drive. The charge transfer statistics at finite temperature can be interpreted in terms of multiple charge transfers with probabilities which depend on energy and temperature.

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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