2014/12/12 by Michael Ridley, A. MacKinnon, Angus MacKinnon +4
Engineering · Physics and Astronomy · #Advanced Memory and Neural Computing #Advancements in Semiconductor Devices and Circuit Design #FOS: Physical sciences #Integrated Circuits and Semiconductor Failure Analysis #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #cond-mat.mes-hall
paper · pdf · doi:10.48550/arxiv.1412.4118
21 pages, 14 figures
arxiv created 2014/12/12 · openalex publication_date 2014/12/12 · arxiv updated 2014/12/16 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We apply the Nonequilibrium Green's Function (NEGF) formalism to the problem of a multi-terminal nanojunction subject to an arbitrary time-dependent bias. In particular, we show that taking a generic one-particle system Hamiltonian within the wide band limit approximation (WBLA), it is possible to obtain a closed analytical expression for the current in each lead. Our formula reduces to the well-known result of Jauho et. al. [doi:10.1103/PhysRevB.50.5528] in the limit where the switch-on time is taken to the remote past, and to the result of Tuovinen et. al. [doi:10.1088/1742-6596/427/1/012014] when the bias is maintained at a constant value after the switch-on. As we use a partition-free approach, our formula contains both the long-time current and transient effects due to the sudden switch-on of the bias. Numerical calculations performed for the simple case of a single-level quantum dot coupled to two leads are performed for a sinusoidally-varying bias. At certain frequencies of the driving bias, we observe `ringing' oscillations of the current, whose dependence on the dot level, level width, oscillation amplitude and temperature is also investigated.