Ab-initio technique to examine the mechanical, electronic, optical and thermal features of direct band-gap semiconductors APtSn (A = Ti, Zr, Hf, Th): an extended review
摘要
Half-Heusler (HH) materials played a significant role in the renewable energy sector through the exchange of waste heat to electric power. In existing research, the detailed exploration of structural, elastic, electronic, optical as well as thermal features of HH materials APtSn (A = Ti, Zr, Hf, Th) have been done expending ab-initio routine. Furthermore, current research represents the extended version of earlier research and accounts for missing information of ThPtSn. The estimated data showed good alignment with the literature results which confirm the reliability of this work. The thermodynamical and dynamical stability of APtSn (A = Ti, Zr, Hf, Th) has been ensured from negative formation enthalpy and positive phonon dispersion curves. Mechanical stability of APtSn (A = Ti, Zr, Hf, Th) is confirmed from the calculated elastic constants as they hold Born’s stability criterion. Mechanical properties analysis showed higher bulk modulus, shear modulus, and Young’s modulus which confirmed the high resistance to volume, shear and longitudinal deformation respectively. According to Vicker’s hardness analysis only the phase HPtSn lies just above the border line (8 GPa) shows the hard nature whereas the other phases APtSn (A = Ti, Zr, Th) show soft nature. High machinable index, µm (> 2) proposing fewer friction and enriched lubricating performance, which ensured the industrial applications of APtSn (A = Ti, Zr, Hf, Th). The analysis of electronic band structures ensured that the studied phases APtSn (A = Ti, Zr, Hf, Th) have tiny band gap of 0.89 eV, 1.05 eV, 0.95 eV, and 0.74 eV respectively. However the band gap values using the TB-mbj method are 0.96 eV, 1.17 eV, 1.08 eV and 0.97 eV APtSn (A = Ti, Zr, Hf, Th) respectively. The calculated band gaps are found to be more accurate with the experimental values whereas the other methods showed overestimated data compared to experimental values. Therefore, the present study conveys a good message to the researcher for band gap evaluation. Very good absorption in the visible region and optical conductivity in the UV region is obtained. The high reflectivity in the energy regions 4–12 eV ensures the possible applications of APtSn (A = Ti, Zr, Hf, Th) as perfect solar reflector in this energy range. High melting temperature and very lesser thermal conductivity, Kmin ensured that these materials can be used as thermal barrier coating (TBC) materials to avoid solar heating.