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Indexed by:期刊论文

Date of Publication:2010-01-01

Journal:JOURNAL OF SOLID STATE CHEMISTRY

Included Journals:SCIE、EI

Volume:183

Issue:1

Page Number:136-143

ISSN No.:0022-4596

Key Words:Intermetallics; Band structures; Elastic properties; Heats of formation; First-principle calculations

Abstract: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(36)Sn(23) and CaPb are mechanically unstable phases. Results on the electronic energy band and densities of states also indicated that Ca(3)Si(4) is an indirect band gap semiconductor with a band gap of 0.598 eV, and Ca(2)Si, Ca(2)Ge, Ca(2)Sn, and Ca(2)Pb 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. (C) 2009 Elsevier Inc. All rights reserved.