دنیای نانو

دنیای نانو

بررسی ابتدا به ساکن خواص الکترونی و نوری ترکیب CeO2

نوع مقاله : مقاله پژوهشی

نویسندگان
1 گروه فیزیک، واحد اهواز ، دانشگاه آزاد اسلامی ، اهواز، ایران
2 مرکز تحقیقات مهندسی سطح پیشرفته و نانو مواد، گروه فیزیک، واحد اهواز ، دانشگاه آزاد اسلامی ، اهواز، ایران
چکیده
در این تحقیق، خواص الکترونی و نوری دی اکسید سریوم (CeO2) با به کارگیری روش شبه‌پتانسیل در چارچوب نظریه‌ی تابع چگالی و با استفاده از کد محاسباتی کوانتوم اسپرسو تحت شرط پایستگی بار و در دو تقریب تبادلی- همبستگی LDA و GGA مورد بررسی قرار گرفت. پس از اینکه ساختار دی اکسید سریوم بهینه‌سازی شد، محاسبات مربوط به بررسی خواص الکترونی و نوری ترکیب دی اکسید سریوم انجام شد. در بخش خواص الکترونی، نتایج بدست آمده با داده‌های گزارش شده در تحقیقات پیشین مقایسه گردید و نشان داده شد که تقریب چگالی موضعی (LDA) بیشترین انطباق را با مقادیر تجربی و نظری دارد. گاف نواری، ساختار نواری و چگالی حالات محاسبه و مورد تحلیل قرار گرفت. تقریب LDA مقدارگاف نواری را eV 5/5 نشان داد، در حالی که تقریب شیب تعمیم یافته (GGA) به دلیل همپوشانی ترازهای انرژی با سطح فرمی، قادر به تعیین دقیق گاف نواری نبوده وگاف مشخصی برای ترکیب دی اکسید سریوم ارائه نداد. در بخش خواص نوری، بخش های حقیقی و موهومی تابع دی الکتریک مورد بررسی قرار گرفت. ضرایب خاموشی، شکست و بازتاب استخراج گردید. با استفاده از محاسبه طیف اتلاف انرژی گاف نوری ترکیب دی اکسید سریوم eV 7/2 بدست آمد.
کلیدواژه‌ها
موضوعات

عنوان مقاله English

First-Principles Investigation of the Electronic and Optical Properties of CeO2 Compound

نویسندگان English

Somaieh Azimi 1
Azadeh Haghighatzadeh 2
Azadeh Aezami 1
1 Department of Physics, Ahv.C., Islamic Azad University, Ahvaz, Iran
2 Advanced Surface Engineering and Nano Materials Research Center, Department of Physics, Ahv.C., Islamic Azad University, Ahvaz, Iran
چکیده English

In this research, the electronic and optical properties of cerium dioxide (CeO2) were investigated by employing the pseudopotential method within the framework of density functional theory and using the Quantum ESPRESSO computational code under charge conservation, and within the two exchange-correlation approximations of LDA and GGA. In the first stage, the structure of cerium dioxide was simulated, and then the structural optimization and precise calculation of the properties of this compound were performed. In the section on electronic properties, the obtained results were compared with the data reported in previous studies, and it was demonstrated that the Local Density Approximation (LDA) has the closest agreement with the experimental and theoretical values. The band gap, band structure, and density of states were calculated and analyzed. The LDA approximation showed the band gap value to be 2.5 eV, whereas the Generalized Gradient Approximation (GGA), due to the overlap of energy levels with the Fermi level, was not able to determine the band gap precisely and did not present a specific gap. In the part of optical properties, the real and imaginary parts of the dielectric function were investigated, and based on them, the extinction, refraction, and reflection coefficients were extracted. Also, the energy loss spectrum was determined, which showed the optical gap of this compound to be 2.7 eV.

کلیدواژه‌ها English

Quantum ESPRESSO Code
Density Functional Theory
GGA Approximation
LDA Approximation
Cerium Dioxide
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دوره 21، شماره 81
زمستان 1404
صفحه 52-62

  • تاریخ دریافت 06 دی 1404
  • تاریخ بازنگری 24 بهمن 1404
  • تاریخ پذیرش 03 اسفند 1404