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Nonequilibrium Green’s function theory for transport and gain properties of quantum cascade structures

Lee, Shun-Chen and Wacker, Andreas LU (2002) In Physical Review B (Condensed Matter and Materials Physics) 66.
Abstract
The transport and gain properties of quantum cascade (QC) structures

are investigated using a nonequilibrium Green's function (NGF) theory

which includes quantum effects beyond a Boltzmann transport description.

In the NGF theory, we include

interface roughness, impurity, and electron-phonon scattering

processes within a self-consistent Born approximation,

and electron-electron scattering in a mean-field approximation.

With this theory we obtain a description of the nonequilibrium

stationary state of QC structures under an applied bias,

and hence we determine transport properties, such as the current-voltage

characteristic of these structures. We... (More)
The transport and gain properties of quantum cascade (QC) structures

are investigated using a nonequilibrium Green's function (NGF) theory

which includes quantum effects beyond a Boltzmann transport description.

In the NGF theory, we include

interface roughness, impurity, and electron-phonon scattering

processes within a self-consistent Born approximation,

and electron-electron scattering in a mean-field approximation.

With this theory we obtain a description of the nonequilibrium

stationary state of QC structures under an applied bias,

and hence we determine transport properties, such as the current-voltage

characteristic of these structures. We define two contributions

to the current, one contribution driven by the scattering-free

part of the Hamiltonian, and the other driven by the scattering

Hamiltonian. We find that the dominant part of the current

in these structures, in contrast to simple superlattice

structures, is governed mainly by the scattering Hamiltonian.

In addition, by considering the linear response of the

stationary state of the structure to an applied optical field,

we determine the linear susceptibility, and

hence the gain or absorption spectra of the structure.

A comparison of the spectra obtained from the more rigorous

NGF theory with simpler models shows that the spectra tend to

be offset to higher values in the simpler theories. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
66
publisher
American Physical Society
external identifiers
  • Scopus:0037116041
ISSN
1098-0121
DOI
10.1103/PhysRevB.66.245314
language
English
LU publication?
no
id
43b0af42-941d-4b6f-8869-236242d10a66 (old id 1360479)
date added to LUP
2009-03-17 15:44:49
date last changed
2016-12-04 04:37:15
@misc{43b0af42-941d-4b6f-8869-236242d10a66,
  abstract     = {The transport and gain properties of quantum cascade (QC) structures<br/><br>
are investigated using a nonequilibrium Green's function (NGF) theory<br/><br>
which includes quantum effects beyond a Boltzmann transport description.<br/><br>
In the NGF theory, we include<br/><br>
interface roughness, impurity, and electron-phonon scattering<br/><br>
processes within a self-consistent Born approximation,<br/><br>
and electron-electron scattering in a mean-field approximation.<br/><br>
With this theory we obtain a description of the nonequilibrium<br/><br>
stationary state of QC structures under an applied bias,<br/><br>
and hence we determine transport properties, such as the current-voltage<br/><br>
characteristic of these structures. We define two contributions<br/><br>
to the current, one contribution driven by the scattering-free<br/><br>
part of the Hamiltonian, and the other driven by the scattering<br/><br>
Hamiltonian. We find that the dominant part of the current<br/><br>
in these structures, in contrast to simple superlattice<br/><br>
structures, is governed mainly by the scattering Hamiltonian.<br/><br>
In addition, by considering the linear response of the<br/><br>
stationary state of the structure to an applied optical field,<br/><br>
we determine the linear susceptibility, and<br/><br>
hence the gain or absorption spectra of the structure.<br/><br>
A comparison of the spectra obtained from the more rigorous<br/><br>
NGF theory with simpler models shows that the spectra tend to<br/><br>
be offset to higher values in the simpler theories.},
  author       = {Lee, Shun-Chen and Wacker, Andreas},
  issn         = {1098-0121},
  language     = {eng},
  publisher    = {ARRAY(0xad7efb8)},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Nonequilibrium Green’s function theory for transport and gain properties of quantum cascade structures},
  url          = {http://dx.doi.org/10.1103/PhysRevB.66.245314},
  volume       = {66},
  year         = {2002},
}