Investigation on electronic structure and luminescence mechanism of CaF2:Eu3+ from first principles calculations

Abstract

In this work, we present the results of theoretical calculations based on the density functional theory (DFT) of structural, electronic and optical properties of CaF2 crystal doped with Eu3+ ion. This study covers both ground and excited states of considered material by fixing spin magnetic moment 6μB and 4μB, respectively. The Eu3+ doping induces slight displacement of its nearest neighbors. The presence of Eu3+ ion is confirmed by the calculated charge density and magnetic moment. Some electronic states belonging to 4f orbital are found in the forbidden energy region of CaF2 and the spin flipping of one 4f electron of Eu3+ caused by the excitation is demonstrated by means of the computed electronic properties. The absorption spectra of CaF2:Eu3+ is calculated and compared with that of pure CaF2. Finally, the possible mechanism of luminescence is proposed based on the obtained electronic and optical properties.