بررسی ویژگی‌های ساختاری و اپتیکی ترکیب MgAl2O4با استفاده از نظریۀ تابعی چگالی

نویسندگان

چکیده
در این مقاله ساختار الکترونی، خواص ساختاری از جمله ثابت شبکه، مدول حجمی، تراکم‌پذیری، چگالی و خواص اپتیکی اکسید اسپینل (MgAl2O4) بررسی میشود. محاسبه‌ها با استفاده از روش امواج تخت تقویت‌شدۀ خطی با پتانسیل کامل (FP-LAPW) در چارچوب نظریۀ تابعی چگالی و با استفاده از نرم‌افزار WIEN2k صورت گرفته است. پارامترهای ساختاری و گاف نواری با تقریب‌های مختلف بررسی شده است و نتایج پارامترهای ساختاری در تقریب GGA-WC نتایج گاف نواری در تقریبLDA با نتایج تجربی سازگاری بهتری داشته لذا در ادامه روش MBJ به همراه دو تقریب ذکر شده به کار گرفته شده است. گاف نواری با استفاده ازتقریبGGA-WC تطابق بهتری با تجربه داشت بنابراین بررسی سیستم تحت فشار با استفاده از تقریب MBJ+GGA(WC) انجام گرفت. خواص اپتیکی نظیر تابع دی­الکتریک، ضریب­شکست، ضریب­خاموشی، تابع اتلاف­انرژی، بررسی شده است. نتایج به دست آمده از ساختار نواری نشان می­دهند که این ترکیب عایق است و گاف نواری 67/7 الکترون‌ولت دارد. ضریب شکست 55/1 محاسبه شد. نتایج محاسبه شده در توافق خوبی با نتایج نظری و تجربی دیگران است.

کلیدواژه‌ها


عنوان مقاله English

Investigation of structural and optical propertie of MgAl2O4 using density functional theory

نویسندگان English

hamdollah salehi
zohreh javdani
چکیده English

In this article, the electronic and structural properties of MgAl2O4 such as lattice constant, bulk modulus, compressibility, density; and optical propertieshave been investigated . Calculations were performed using the Full-Potential-Linearized Argument Plane Wave (FP-LAPW) method in the density functional theory framework by Wien2k code. Structural properties and band gap have been studied with different approximations. Compared to experimental results,the results of structural properties withGGA-WCapproximation and the results of band gap withLDA approximation have been better compatibility, therefor; the MBJ method along with two mentioned approximations has been used later. The effect of pressure on MgAl2O4 have been investigated withMBJ+GGA(WC)approximation. The optical properties such as dielectric function, refraction index, extinction coefficient and energyloss function have been studied. The obtained results from band structure shows that MgAl2O4is an insulator and the band gap is equal to 7.67 eV. Therefraction indexis equal to 1.55. The obtained results have been in good agreement with other theory and experimental results.

کلیدواژه‌ها English

MgAl2O4
band gap
density functional theory
Structural properties
hubard
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