
\documentstyle{report}
\topmargin  0.10in
\textheight 9.0in
\textwidth  6.0in 

\begin{document}


\begin{center}
{\Large {\bf Nonequilibrium Green's Function Formulation of  Quantum Transport
Theory for Multi-band Semiconductors}}\\[0pt]
{\large Peiji Zhao$^1$, N. J. M. Horing$^2$, D. L. Woolard$^3$, H. L. Cui$^2$ \\[0pt]
}
\end{center}

\begin{flushleft}
\large
{\it $^1$ Department of Electrical and Computer Engineering\\
North Carloina State University, Raleigh, NC 27695}\\
{\it $^2$ Department of Physics and Engineering Physics\\
Stevens Institute of Technology, Hoboken, NJ 07030}\\
{\it $^3$ Army Research Office, Research Triangle Park, NC 27709}
\end{flushleft}

\normalsize 

We present a nonequilibrium Green's function formulation of
many-body quantum transport theory for multi-band semiconductor systems with a phonon bath.
The equations are expressed exactly in terms of single particle
nonequilibrium Green's functions and self-energies, treating the open
electron-hole system in weak interaction with the bath. A decoupling
technique is employed to separate the individual band Green's function
equations of motion from one another, with the band-band interaction effects
embedded in ''cross-band'' self-energies. 
This nonequilibrium Green's function formulation of quantum transport theory
is amenable to solution by parallel computing because of its formal
decoupling with respect to interband interactions. Moreover, this
formulation also permits coding the simulator of an $n$-band semiconductor
in terms of that for an ($n-1$)-band system, in step with the current tendency
and development of programming technology. Finally, the focus of these
equations on individual bands provides a relatively direct route for the
determination of carrier motion in energy bands, and to delineate the
influence of intra- and inter-band interactions.  A graphic method is presented for writing out the dressed self-energies and the cross-band Green's functions.
A detailed description is
provided for three-band semiconductor systems. 
\end{document}

