Ultra-Low Thermal Conductivity in W/Al₂O₃ Nanolaminates

Atomic layer deposition and magnetron sputter deposition were used to synthesize thin-film multilayers of W/Al₂O₃. With individual layers only a few nanometers thick, the high interface density produced a strong impediment to heat transfer, giving rise to a thermal conductivity of ∼0.6 watts per meter per kelvin. This result suggests that high densities of interfaces between dissimilar materials may provide a route for the production of thermal barriers with ultra-low thermal conductivity.