Thermal conductivity of M@C82 [M = Dy, Gd] thin films

Abstract

Temperature dependent Raman spectra of a Dy@C82 thin film are investigated between 80 and 300 K. The first order temperature coefficient is evaluated for both Dy–C and C–C vibrational modes which reveals the presence of thermal and anharmonic contributions to the phonon hardening at low temperatures. The Dy–C mode broadens while decreasing the temperature revealing that the electron–phonon coupling is dominant over phonon–phonon coupling at low temperatures. In addition, laser-power dependent Raman spectra of Dy@C82 and Gd@C82 have been analyzed for estimating their first order power coefficients and the thermal conductivities.