Effect of Simultaneous Electric Current on Thermal Conductivity

Abstract

Experimental studies of thermal conductivity may be divided into two classes: (1) empirical studies of a given device to obtain specific data; and (2) more basic studies with the goal of improving performance through changes in material or design. For the first class of studies the most elementary concepts of the coefficient of thermal conductivity, λt, are generally satisfactory. For more basic studies, however, a clear understanding of the relation between theoretical concepts (such as lattice thermal conductivity, λl) and an experimentally measured quantity is essential. An example of confusion in this regard is the statement in Berman’s book on thermal conductivity1 that λl in a semiconductor is reduced by the small concentration of impurity atoms (about 0.001%) used in doping. In fact λl is virtually constant, but λt is being affected by changes in thermopower2. The aim of this paper is to describe a simple, correct procedure for the analysis of thermal conductivity, a procedure that facilitates theoretical interpretation of experimental data. The particular problem of thermal conduction in the presence of an electric current will be analyzed.