Environmental Engineering Reference
In-Depth Information
4.3.4
Ballistic Thermal Transport Contributed by the
Coupled P-SV Waves in Low-Dimensional Quantum
Structures
Li
et al.
[58] systematically investigated the ballistic thermal-
transport properties of the coupled P-SV waves through a T-shaped
quantum structure and provided a detailed comparison between
the SH waves and the coupled P-SV waves. It is demonstrated that
the coupled P-SV waves show some new transmission characters,
differentfromthecasefortheSHwavesduetothemodeconversion
and mode mixing effect. For example, when the P wave is incident,
zero transmission only occurs at low frequency where only the zero
mode of P wave can be excited in such a waveguide. For higher
frequency, when the first mode of SV wave starts to be excited,
there is a rapid decrease in transmission coe
cient. These are
inconsistent with the results of the SH wave for the same structural
parameters.Inaddition,comparedtotheSHwave,inlow-frequency
region, the transmission coe
cient of the P wave becomes more
complicated and exhibitsmore resonance transmission peaks.
4.4 Summary
In the present review, we introduce the elastic continuum model
to describe the elastic phonon modes in low-dimensional nanos-
tructures,andpresentthenecessarydetailsofthescattering-matrix
method to calculate the transmission coe
cient and the Landauer
formula for the thermal conductance. Then the effects of inhomo-
geneities, boundary conditions, dimensions, etc., on the ballistic
phonon transmission and thermal conductance are summarized
and reviewed. Results show some interesting physical properties,
such as the universal quantum thermal conductance, periodic
transmission behaviors, stop-frequency gap, and so on. In fact,
thermal management has become an essential issue for continuing
progress in the electronic industry. The present results provide
an e
cient way to control the thermal conductance artificially by
adjustingtheparametersoftheproposednanostructures.Thesewill
be helpful to not only comprehensively understand the behaviors
