Environmental Engineering Reference
In-Depth Information
Figure 2.8
The temperature dependence of the ratio
κ
vac(SW)
/
κ
p
for the
SWNTwiththevacancy(SWdefect).Theblack,red,andbluesolid(dashed)
curves are
κ
vac(SW)
/
κ
p
for(6,6), (8,8), and (10,10)SWNTs, respectively.
2.3.3
Isotope Effects on Thermal Transport in Carbon
Nanotubes
In this subsection, we present applications of Landauer-NEGF
method to the coherent phonon transport in isotope-disordered
SWNTs with randomly distributed
13
Cand
14
C [24, 25]. Since
the coexistence of
13
Cand
14
C isotopes and the resultant elastic
scattering cause the interference between coherent phonons,
the isotope-disordered SWNTs is expected to exhibit remarkable
phonon transport phenomena originating from the wave nature of
phonons.
2.3.3.1 Characteristic lengths: mean free path and localization
length
Coherent-phonon transport is classified into three regions based on
arelation amongthelength
L
ofthescattering region, themean free
path
l
MFP
(
ω
), and the localization length
ξ
: the ballistic regime for
L
l
MFP
(
ω
), the diffusive regime for
l
MFP
(
ω
)
L
ξ
(
ω
), and the