بررسي ابتدا به ساكن اثرافزودن كروم روي خواص الكترونيكي آلومينا

Ab initio investigation of effect of Cr impurity on electronic properties of Alumina

اثر افزودن ناخالصي كروم روي خواص الكترونيكي α − Al2O3 با استفاده از محاسبات انرژي كل ابرسلول شبكه α − Al2O3 :Cr در چارچوب نظريه تابعي چگالي و تقريب هاي LSDA ، GGA و LSDA+U مورد بررسي قرار گرفت. مقدار انرژي براي اولين گذار از تراز پر ناخالصي به تراز رسانش توسط روش GGA+U به خوبي محاسبه شد. مشاهده گرديد كه Cr باعث كاهش مقدار گاف انرژي α − Al2O3 مي شود و مشاركت ترازهاي كروم در ميان گاف انرژي اين ماده مشاهده گرديد.

The electronic properties of a single Cr impurity in 2 3 α − Al O are studied by means of supercell total-energy calculations using a first-principles method based on density-functional theory . The calculations were performed using the full potential– linearized augmented plane wave (FP-LAPW) with the GGA, LSDA and LSDA+U methods. The calculated value of the first excitation from the occupied impurity state to the conduction band was reproduced well by LSDA+U method, while GGA and LSDA yielded values that were less than the experimental value. The impurity bands contribution are in gap region of 2 3 α − Al O