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Structural, elastic, electronic and vibrational properties of XAl2O4 (X = Ca, Sr and Cd) semiconductors with orthorhombic structure      
Yazarlar
Salih Akbudak
Adıyaman Üniversitesi, Türkiye
Doç. Dr. Abdullah CANDAN Doç. Dr. Abdullah CANDAN
Kırşehir Ahi Evran Üniversitesi, Türkiye
A K Kushwaha
A C Yadav
Gökay Uğur
Gazi Üniversitesi, Türkiye
Şule Uğur
Gazi Üniversitesi, Türkiye
Özet
Structural, elastic, electronic and vibrational properties of XAl2O4 (X = Ca, Sr and Cd) compounds with orthorhombic structure are studied by first principles method within generalized gradient approximation. The calculated negative formation enthalpy for each compounds indicates the thermodynamical stability of the studied phase. Band structure calculations reveal that CaAl2O4, SrAl2O4 and CdAl2O4 compounds have a direct band gap of 4.86, 4.54 and 2.46 eV, respectively. Besides, from the analysis of the band gap values, one can notice that the replacement of Ca atoms by Sr and Cd atoms in these compounds reduces the band gap energy values. It is also observed that the CaAl2O4, SrAl2O4 and CdAl2O4 compounds are less compressible along b-axis and their compressibility decreases in the sequence SrAl2O4 > CdAl2O4 > CaAl2O4. Similarly, it is also noticeable that the CaAl2O4 compound have more resisting power against the monoclinic shear distortion along {100} plane and along {110} direction compared to CdAl2O4 and SrAl2O4 compounds. Moreover, Cauchy pressures confirm that the CaAl2O4 and SrAl2O4 compounds are ductile while the CdAl2O4 compound is brittle in nature. This fit very well with the forecast from B/G relation. The calculated elastic constants and the phonon dispersion relations of the studied compounds show that these compounds are both mechanically and dynamically stable. Moreover the temperature dependence of the specific heat and entropy have been discussed in detail and calculated Debye temperature is in good agreement with the related study in literature. (C) 2019 Elsevier B.V. All rights reserved.
Anahtar Kelimeler
Orthorhombic structure, Semiconductor, Elastic constants, Phonon dispersion curves
Makale Türü Özgün Makale
Makale Alt Türü SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale
Dergi Adı JOURNAL OF ALLOYS AND COMPOUNDS
Dergi ISSN 0925-8388
Dergi Tarandığı Indeksler SCI-Expanded
Dergi Grubu Q1
Makale Dili İngilizce
Basım Tarihi 08-2019
Cilt No 809
Sayı 1
Sayfalar 151773 / 0
Doi Numarası 10.1016/j.jallcom.2019.151773
Makale Linki https://linkinghub.elsevier.com/retrieve/pii/S0925838819330063