Ab initio lattice thermal conductivity of bulk and thin-film α-Al2O3. (22nd August 2018) - Dongre, Bonny
Abstract: Abstract : The thermal conductivities ( κ ) of bulk and thin-film α -Al2 O3 are calculated from first principles using both the local density approximation (LDA) and the generalized gradient approximation (GGA) to exchange and correlation. The room temperature single-crystal LDA value ~39 W/m K agrees well with the experimental values ~35–39 W/m K, whereas the GGA values are much smaller ~26 W/m K. Throughout the temperature range, LDA is found to slightly overestimate κ, whereas GGA strongly underestimates it. We calculate the κ of crystalline α -Al2 O3 thin films and observe a maximum of 79% reduction for 10 nm thickness.