Lattice thermal transport in nanocomposites

<p>Gyaneshwar Srivastava</p>

Lattice thermal transport in nanocomposites

Gyaneshwar Srivastava

University of Exeter, UK

: J Chem Appl Chem Eng

Abstract

Parameter-free description of thermal conductivity of solids over a broad temperature range has been a long standing problem. In this talk I will describe a recent development of the theory of lattice thermal transport in non-metallic materials, including a semi ab-inito treatment of three-phonon and four-phonon interactions. After successfully reproducing experimental results for Si and Ge in the temperature range 5-1300 K, predictions will be made for the conductivity results of bulk as well as monolayer transition metal dichalcogenides (TMDs) MoS2, WS2 and MoTe2. I will then describe how this theory is currently being developed further to determine the lattice thermal conductivity of ultrathin nanocomposites, such as planar superlattices, nanowire superlattices and nanodot superlattices of periodicities less than 10 nm. For nanocomposite structure of experimentally grown sizes, i.e. inserts of low to medium nm sizes in host materials of micron sizes, an effective medium theory that accounts for the anisotropic nature of the conductivities of the host, the insert and the insert-host interface region will be described. From an analysis of accurate numerical results obtained for Si inserts in Ge host, and WS2 inserts in MoS2 host, we will draw useful conclusions regarding appropriate choices of key physical parameters for tuning lattice thermal conductivity of nanocomposites in general.