Interaction of thermal phonons with interfaces

In this chapter we will first explore the connection between interface scattering and thermal transport using the Boltzmann transport equation (BTE). It will be shown that Boltzmann transport provides a convenient method for considering boundary scattering in nanochannel structures. For internal interfaces such as grain boundaries found in polycrystals, it is more natural to consider transmission and reflection across a single boundary. In this regard we will discuss theories related to interface thermal resistance. Our qualitative discussion of the theories of phonon transport will be followed by a discussion of experimental techniques for measuring thermal transport. We end this chapter by giving a detailed description of two complementary experimental techniques for measuring the influence of interfaces on thermal phonon transport.