Thermal conductivity of half-Heusler superlattices

Thin films and superlattices (SLs) of TiNiSn and ZrHfNiSn layers have been grown by dc magnetron sputtering on MgO (100) substrates to reduce the thermal conductivity, aiming for improvement of the thermoelectric figure of merit ZT. The thermal conductivity of 1 Wm−1K−1 was measured by the differential 3ω method for an SL with a periodicity of 8.8 nm. In addition to x-ray diffraction analysis of the SL crystal structure, smooth interfaces were confirmed by scanning/transmission electron microscopy.