Environmental Engineering Reference
In-Depth Information
Figure 3.4
Work flow of the NEGF method for the case of phonon-phonon
interactions are included in the calculation.
obtained Green's functions to construct many-body self-energies
again,and iterations are done tillgetting converged
G
r
and
G
<
.
Usually we neglect the term
n
in NEGF calculations, because
computing
n
iscomplexandonlyfeasibleforsmallmodelsystems.
This is a safe approximation for general uses because the influence
of anharmonicinteractions isonly important athigh temperatures.
3.2.3
NEGF and Thermal-Transport Properties
Once getting the Green's functions, we can obtain all the one-
particle quantities relevant to thermal transport, including phonon
density of states (DOS), thermal current, thermal conductance,
phonon transmission function and so on. Consequently, a complete
physical picture of quantum thermal transport can be established.
In the following, we show the relation between NEGF and thermal-
transport properties.
