Suppressed Umklapp scattering of β-FeSi₂ thin film and single crystalline nanowires

Thermal conductivity is an intriguing physical property in the nanometer or quantum regime. In this study, we report the growth and thermal conductivity of β-FeSi₂ thin film and single crystalline nanowires. The sample structures and chemical composition were identified by standard microscopy techniques. The temperature-dependent thermal conductivity of the thin film was measured by the 3ω method, whereas that of the nanowires was conducted by a suspended pattern technique. Temperature-dependent thermal conductivity was found to increase gradually from 300 to 500 K due to the effect of surface scattering. The experimental evidence presented herein is the suppression of Umklapp transport at the nanoscale near room temperature and the potential application of nanoengineered β-FeSi₂ for future design of thermoelectric materials.