Half-Heusler compounds are an impressive class of materials with a huge potential for different applications such as in future energy, especially in the fields of thermoelectrics and solar cells. We present ab fnitio ...Half-Heusler compounds are an impressive class of materials with a huge potential for different applications such as in future energy, especially in the fields of thermoelectrics and solar cells. We present ab fnitio total energy calculations within the modified Becke-Johnson generalized gradient approximation （mBJ-GGA） to obtain the physical properties of SrAlGa compounds. The structural, elastic, acoustic, electronic, chemical bonding, optical, and thermoelectric properties are calculated and compared with the available calculation data. The SrAlGa is found to be a small-band-gap （0.125-0.175 eV） material, suitable for thermoelectric applications with a relatively high Seebeck coefficient. Also, SrAIGa has the potential in the optoelectronic applications due to high optical conductivity and reflectivity in the infrared and visible region of electromagnetic spectra.展开更多
A new potential approximation known as modified Becke-Johnson based on density functional theory is applied to compute the electronic band profile and optical response of CdIn2O4, CdGa2O4 and CDAl2O4 compounds. The di...A new potential approximation known as modified Becke-Johnson based on density functional theory is applied to compute the electronic band profile and optical response of CdIn2O4, CdGa2O4 and CDAl2O4 compounds. The direct band gap with common LDA, GGA and EV-GGA is drastically underestimated compared with modified 13ecke-Johnson approximation, whose results are significantly closer to the experimental findings. The optical properties like dielectric constant, refractive index, reflectivity, optical conductivity and absorption coefficient axe also computed. A unique characteristic associated with cation replacement is studied; the replacement of cation In by Ga and Ga by AI significantly reduces the direct energy band gap in these compounds. This variation is of crucial importance for band gap dependent optical properties of these compounds, which is also proof for applications of these compounds in optoelectronic devices.展开更多
文摘Half-Heusler compounds are an impressive class of materials with a huge potential for different applications such as in future energy, especially in the fields of thermoelectrics and solar cells. We present ab fnitio total energy calculations within the modified Becke-Johnson generalized gradient approximation （mBJ-GGA） to obtain the physical properties of SrAlGa compounds. The structural, elastic, acoustic, electronic, chemical bonding, optical, and thermoelectric properties are calculated and compared with the available calculation data. The SrAlGa is found to be a small-band-gap （0.125-0.175 eV） material, suitable for thermoelectric applications with a relatively high Seebeck coefficient. Also, SrAIGa has the potential in the optoelectronic applications due to high optical conductivity and reflectivity in the infrared and visible region of electromagnetic spectra.
文摘A new potential approximation known as modified Becke-Johnson based on density functional theory is applied to compute the electronic band profile and optical response of CdIn2O4, CdGa2O4 and CDAl2O4 compounds. The direct band gap with common LDA, GGA and EV-GGA is drastically underestimated compared with modified 13ecke-Johnson approximation, whose results are significantly closer to the experimental findings. The optical properties like dielectric constant, refractive index, reflectivity, optical conductivity and absorption coefficient axe also computed. A unique characteristic associated with cation replacement is studied; the replacement of cation In by Ga and Ga by AI significantly reduces the direct energy band gap in these compounds. This variation is of crucial importance for band gap dependent optical properties of these compounds, which is also proof for applications of these compounds in optoelectronic devices.
