Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 35: Postersession Transport: Nanoelectronics, Quantum Coherence and Quantum Information, Fluctuations and Noise

TT 35.4: Poster

Wednesday, March 25, 2009, 14:00–18:00, P1A

Time-resolved Electron Transport through Quantum Dot Systems — •Alexander Croy and Ulf Saalmann — Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany

The investigation of time-resolved currents in mesoscopic devices has gained a lot of interest over the past few years. There has been a lot of experimental and theoretical progress in realizing, modeling and understanding time-dependent electron transport.

In this context we study theoretically the time-resolved electric currents flowing through single and double quantum dots that are subject to a voltage pulse. An established tool in this regard is the non-Markovian quantum master equation (QME) for the many-body density matrix describing the state of the quantum dot system. Usually the QME is taken up to second order in the dot-reservoir coupling. For QMEs of higher order in the coupling not as many results are available.

In the present work we numerically solve a QME including terms up to fourth order and give results of the time-resolved occupation and the currents flowing through the system. Complementary to that we present a new method for treating time-dependent non-equilibrium Green function calculations in the wide-band limit. We show a comparison of the results obtained from both methods for the non-interacting resonant level model, indicating that the additional terms are important to describe the electric current.