Unified representation of thermal conductivities for movement of electrons and lattice vibration of atoms

Abstract The thermal conductivities of metals and insulators (ceramics) with varying electronic band structures have been expressed in past studies using a harmonic oscillator model of constituent atoms. This paper further analyzed this and established that though free electrons located near Fermi level (EF) are responsible for thermal conduction of metals, it is possible to represent the measured thermal conductivity as product of a specific heat of the lattice vibration (Clv) for 1 m3 solid and equivalent thermal diffusivity of lattice vibration (qαe, q = Cev/Clv = zπ2 kT/6EF, where αe = thermal diffusivity by free electrons, Cev = specific heat of free electrons included in 1 m3 solid, z = number of activated electrons per one metal atom at EF level, and k = Boltzmann constant). Better understanding of the properties of free electrons contributing to thermal conduction of metals from parameters of equivalent lattice vibration model for an insulator was further explored in this study.