Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 24: Quantum dots and wires: Transport properties II
HL 24.10: Vortrag
Dienstag, 27. März 2007, 16:30–16:45, H15
Realistic simulation of nanowire transistors: A multi-configurational approach to Coulomb effects — •Klaus Michael Indlekofer1, Joachim Knoch1, and Joerg Appenzeller2 — 1CNI, IBN-1, Research Center Jülich GmbH, D-52425 Jülich, Germany — 2IBM T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598, USA
We employ a novel multi-configurational Green’s function approach (MCSCG) [1,2] for the simulation of Coulomb effects in nanowire transistors. The improvement of the MCSCG stems from a self-consistent adaptive division of the large channel Hilbert space into a small subsystem of resonantly trapped states for which a many-body Fock space approach becomes numerically feasible and a strongly coupled rest which can be treated adequately on a mean-field level. The Fock space description allows for the calculation of few-electron Coulomb charging effects beyond mean-field.
We compare a conventional mean-field non-equilibrium Green’s function calculation with the results of the MCSCG. Using the MCSCG method, Coulomb diamonds are obtained at low temperatures while under high temperature conditions the mean-field approximation is retained. From the simulated Coulomb-blockade characteristics we derive effective system capacitances. Quantum confinement effects give rise to corrections, which are crucial for the interpretation of experimentally determined capacitances.
[1] K.M. Indlekofer et al., Phys. Rev. B 72, 125308 (2005).
[2] K.M. Indlekofer et al., Phys. Rev. B 74, 113310 (2006).