First-principles calculations of Mg2X (X = Si, Ge, Sn) semiconductors with the calcium fluorite structure*Project supported by the Fundamental Research Funds for the Central Universities (No. 2013QNA32) and the National Natural Science Foundation of China (No. 11404391). (May 2015)

• Record Type: Journal Article
• Authors: Guo, Sandong
• Is Part Of: Journal of semiconductors. Volume 36:Number 5(2015:May)
• Page Start: 1909
• Publication Date: 2015-05
• Subjects: Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1674-4926/36/5/053002
• Languages: English
• ISSNs: 1674-4926

Abstract

<abstract> <title>Abstract</title> <p>The electronic structures of Mg₂X (X = Si, Ge, Sn) have been calculated by using generalized gradient approximation, various screened hybrid functionals, as well as Tran and Blaha's modified Becke and Johnson exchange potential. It was found that the Tran and Blaha's modified Becke and Johnson exchange potential provides a more realistic description of the electronic structures and the optical properties of Mg₂X (X = Si, Ge, Sn) than else exchange-correlation potential, and the theoretical gaps and dielectric functions of Mg₂X (X = Si, Ge, Sn) are quite compatible with the experimental data. The elastic properties of Mg₂X (X = Si, Ge, Sn) have also been studied in detail with the generalized gradient approximation, including bulk modulus, shear modulus, Young's modulus, Poisson's ratio, sound velocities, and Debye temperature. The phonon dispersions of Mg₂X (X = Si, Ge, Sn) have been calculated within the generalized gradient approximation, suggesting no structural instability, and the measurable phonon heat capacity as a function of the temperature has been also calculated.</p> </abstract>