Determination of the thermal conductivity of nanowires based on the metal–insulator transition of VO2

Abstract

We develop the theoretical foundation to determine the thermal conductivity of a single nanowire by using the optical contrast of the metallic and insulating domains of a VO2 nanowire excited with either a temperature difference or a laser beam. Considering the temperature dependence of the VO2 thermal conductivity, the heat flux and the temperature profile along a VO2 nanowire are obtained and used to derive explicit expressions for the position of the metal/insulator domain interface as a function of the thermal excitation. This relation determines the variations of the metallic and insulating domains’ lengths, which can be employed to retrieve the thermal conductivity of a single nanowire bonded to a VO2 one. Furthermore, the advantages and disadvantages of each thermal excitation are discussed along with the appearance of invariants driving the one-dimensional nonlinear heat conduction along VO2 nanowires.