First-principle studies of Ca– X ( X=Si,Ge,Sn,Pb) intermetallic compounds
The structural properties, elastic properties, heats of formation, electronic structures, and densities of states of 20 intermetallic compounds in the Ca– X ( X=Si, Ge, Sn, Pb) systems have been systematically investigated by using first-principle calculations. Our computational results indicated th...
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Veröffentlicht in: | Journal of solid state chemistry 2010-01, Vol.183 (1), p.136-143 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The structural properties, elastic properties, heats of formation, electronic structures, and densities of states of 20 intermetallic compounds in the Ca–
X (
X=Si, Ge, Sn, Pb) systems have been systematically investigated by using first-principle calculations. Our computational results indicated that with increasing atomic weight of
X, the bulk modulus of Ca–
X intermetallic compounds decreases gradually. It was also found that Ca
36Sn
23 and CaPb are mechanically unstable phases. Results on the electronic energy band and densities of states also indicated that Ca
3Si
4 is an indirect band gap semiconductor with a band gap of 0.598
eV, and Ca
2Si, Ca
2Ge, Ca
2Sn, and Ca
2Pb are direct band gap semiconductors with band gaps of 0.324, 0.265, 0.06, and 0.07
eV, respectively. In addition, it is found that the absolute values of heats of formation for all Ca–
X intermetallics are larger than 30
kJ/mol
atom.
Calculated (a) bulk moduli and (b) shear moduli of Ca–
X system intermetallic compounds. |
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ISSN: | 0022-4596 1095-726X |
DOI: | 10.1016/j.jssc.2009.11.007 |