双掺杂铌酸锂晶体的第一性原理研究

First principles study of doubly-doped LiNbO_3

本文利用第一性原理研究了Mn:Fe:LiNbO_3晶体、Mn:Ru:LiNbO_3晶体和Fe:Ru:LiNbO_3晶体的电子结构和光学性质.通过时电子结构的分析,发现杂质能级的深浅与掺杂元素原子序数有关.原子序数越大,杂质能级越深.通过对Mn:Fe:LiNbO_3晶体、Mn:Ru:LiNbO_3晶体和Fe:Ru:LiNbO_3晶体的吸收谱进行分析,并与单掺杂LiNbO_3晶体的吸收谱进行比较,发现双掺杂在可见光区域吸收率明显提高,约为单掺杂的3倍.Mn:Fe:LiNbO_3晶体分别在380nm和590nm处形成吸收峰,Mn:Ru:LiNbO_3晶体可见光区域吸收率比Mn:Fe:LiNbO_3以及Fe:Ru:LiNbO_3晶体高,分别在450nm附近和660nm附近出现吸收峰,Fe:Ru:LiNbO_3晶体在430nm到600nm之间区域都有较高的吸收率,并在773nm的长波范围有一小的吸收峰.计算结果与双色全息存储(双光子全息存储)所用记录光的波长相符.

The electronic structure and optical properties of doubly-doped lithium niobate crystals Mn. Fe.LiNbO3, Mn.Ru.LiNbO3 and Fe. Ru-LiNbO3 have been studied with the first principles in the paper. It was found that the deepness of impurity energy level is related to the atomic numbers of doped elements by the analysis of their electronic structures. The bigger the atomic number, the deeper the impurity level is. The absorption spectra of these doubly-doped lithium niobates were compared to those of single-doped lithium niobates, and it was found that the absorption of doubly-doped LiNbO3 increases drastically in the range of visible light, which is about three times that of single doped LiNbO3. There are two peaks 380nm and 590nm in the absorption spectrum of Mn. Fe.LiNbO3. Two peaks 450nm and 660nm occur in the absorption spectrum of Mn. Ru： LiNbO3, the absorptivity of which is higher than those of Mn： Fe. LiNbO3 and Fe. Ru ： LiNbO3 in the visible range, while Fe ： Ru.. LiNbO3 has high absorptivity among 430nm and 600nm, and a little peak 770nm in the long wave length range. The calculation showed that the wave length used as recording light in nonvolatile holographic storage is located in the range of high absorptivity.