TIME-DEPENDENT TRANSPORT IN INTERACTING AND NONINTERACTING RESONANT-TUNNELING SYSTEMS
TIME-DEPENDENT TRANSPORT IN INTERACTING AND NONINTERACTING RESONANT-TUNNELING SYSTEMS
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DOI：
10.1103/physrevb.50.5528
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发表时间：
1994-08-15
影响因子：
3.7
通讯作者：
MEIR, Y
中科院分区：
文献类型：
--
作者：
JAUHO, AP;WINGREEN, NS;MEIR, Y
我们考虑在外部时变电压影响下耦合到两个引线的介观区域。时间依赖性与源极和漏极触点、控制隧道势垒高度的栅极或定义介观区域的栅极相耦合。利用Keldysh非平衡格林函数技术，导出了系统中完全非线性、时变电流的形式表达式。该分析承认介观区域的任意相互作用，但引线被视为非相互作用。对于与引线的比例耦合，时间平均电流只是时间平均态密度的化学势之间的积分，通过与引线的耦合加权，与Meir和Wingreen[物理学家]的时间无关的结果非常相似。教理，68,2512(1992)]。给出了精确可解非相互作用共振隧穿系统的解析和数值结果。由于引线和谐振点之间的相干性，电流不会绝热地跟随驱动信号：发现“振铃”电流是对电压脉冲的响应，并且在谐波驱动电压的情况下导致复杂的时间依赖性。我们还建立了一个连接到最近的线性响应计算，并与共振隧道电子-声子散射效应的早期研究。
We consider a mesoscopic region coupled to two leads under the influence of external time-dependent voltages. The time dependence is coupled to source and drain contacts, the gates controlling the tunnel-barrier heights, or to the gates that define the mesoscopic region. We derive, with the Keldysh nonequilibrium-Green-function technique, a formal expression for the fully nonlinear, time-dependent current through the system. The analysis admits arbitrary interactions in the mesoscopic region, but the leads are treated as noninteracting. For proportionate coupling to the leads, the time-averaged current is simply the integral between the chemical potentials of the time-averaged density of states, weighted by the coupling to the leads, in close analogy to the time-independent result of Meir and Wingreen [Phys. Rev. Lett. 68, 2512 (1992)]. Analytical and numerical results for the exactly solvable noninteracting resonant-tunneling system are presented. Due to the coherence between the leads and the resonant site, the current does not follow the driving signal adiabatically: a ''ringing'' current is found as a response to a voltage pulse, and a complex time dependence results in the case of harmonic driving voltages. We also establish a connection to recent linear-response calculations, and to earlier studies of electron-phonon scattering effects in resonant tunneling.