Thermal conductivity reduction and crystal properties evolution in iron silicides induced by doping

Understanding the thermal transport behaviors in the crystal lattice is important for designing semiconducting materials in thermal management. In this work, we investigate the mechanism of the decrease in thermal properties of β-FeSi₂ when Co dopant is introduced to the host crystal. The crystallite size decreases as Co doping increases from 0 to 5 %. The micro-strain and stress increase with increasing doping levels. The decrease in crystallite size and increase in micro-strain/stress indicate the origin of phonons scattering and lattice softening, leading to the reduction in thermal conductivity. This study provides insights into the correlation between the crystal properties evolution and thermal transport in metal silicide compounds which could be useful in thermal-to-energy conversion applications.