Replacing leads by self-energies using non-equilibrium Green's functions

    Authors

    F. Michael;M. D. Johnson

    Comments

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    Abbreviated Journal Title

    Physica B

    Keywords

    non-equilibrium Green's functions; keldysh; mesoscopic transport; TRANSFER-HAMILTONIAN FORMALISM; TUNNELLING CURRENT; TUNNELING CURRENT; JUNCTION; Physics, Condensed Matter

    Abstract

    Open quantum systems consist of semi-infinite leads which transport electrons to and from the device of interest. We show here that within the non-equilibrium Green's function technique for continuum systems, the leads can be replaced by simple c-number self-energies. Our starting point is an approach for continuum systems developed by Feuchtwang. The reformulation developed here is simpler to understand and carry out than the somewhat unwieldly manipulations typical in the Feuchtwang method. The self-energies turn out to have a limited variability: the retarded self-energy Sigma(r) depends on the arbitrary choice of internal boundary conditions, but the non-equilibrium self-energy or scattering function Sigma( < ) which determines transport is invariant for a broad class of boundary conditions. Expressed in terms of these self-energies. continuum non-equilibrium transport calculations take a particularly simple form similar to that developed for discrete systems. (C) 2003 Elsevier B.V. All rights reserved.

    Journal Title

    Physica B-Condensed Matter

    Volume

    339

    Issue/Number

    1

    Publication Date

    1-1-2003

    Document Type

    Article

    Language

    English

    First Page

    31

    Last Page

    38

    WOS Identifier

    WOS:000186812300005

    ISSN

    0921-4526

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