排序方式: 共有46条查询结果,搜索用时 406 毫秒
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基于密度泛函理论平面波赝势法对LaBr3晶体本征点缺陷进行了系统研究.通过第一性原理和热动力学方法,计算得到了不同温度及溴分压下LaBr3晶体中本征点缺陷的缺陷形成能,并讨论了不同环境条件下本征点缺陷的形成能随费米能级的变化关系.计算结果表明,当费米能级位于导带底附近时,LaBr3晶体中的主要点缺陷为Lai…能级位于价带顶附近时,LaBr3晶体中主要的点缺陷为Vlao…VBr在高温/低溴分压相对稳定,Vla在低温/高溴分压更稳定.本文还做出了最稳定点缺陷随温度、溴分压及费米能级变化的三维空间分布图,清晰地呈现了不同条件下,该晶体最可能出现的点缺陷类型,从而为调控晶体的点缺陷改善晶体光学性能提供参考. 相似文献
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基于第一性原理和热动力学方法模拟计算得到了不同温度和氧分压下HfO2晶体本征点缺陷的形成能,并讨论了各种点缺陷的形成能随费米能级变化的规律. 结果表明: 当费米能级在价带顶附近时, 随着温度和氧分压的变化, 出现了不同的最稳定点缺陷(Oi0、VO32+和Hfi4+). 当费米能级大于3.40 eV时, 主要点缺陷是带-4价的Hf 空位. 该晶体除Hf 空位在价带顶附近出现了奇数价态, 其它的点缺陷都只显现偶数价态, 这表明该晶体的点缺陷具有典型的negative-U特性. 本文还计算得到了该晶体可能存在的最稳定点缺陷在温度、氧分压和费米能级三维空间的分布, 这为分析该晶体在不同条件下可能出现的点缺陷类型提供清晰的图像, 为调控晶体点缺陷的形成提供参考. 相似文献
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Electronic structures of PbMoO4 crystals containing F-type colour centres with the lattice structure optimized are studied within the framework of the fully relativistic self-consistent Dirac-Slater theory, using a numerically discrete variational (DV-Xa) method. The calculated results show that F and F+ centres have donor energy levels in the forbidden band. The optical transition energies are 2.166eV and 2.197eV, respectively, corresponding to the 580nm absorption bands in PbMoO4 crystal. The 580nm absorption band in PbMoO4 is originated from the F-type colour centres. 相似文献
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boldmath Study of electronic structures and absorption bands of BaMgF4 crystal with F colour centre 下载免费PDF全文
The electronic structures of BaMgF4 crystals containing an F colour centre are studied within the framework of the fully relativistic self-consistent Direc-Slater theory, using a numerically discrete variational (DV-Xα) method. It is concluded from the calculated results that the energy levels of the F colour centre are located in the forbidden band. The optical transition energy from the ground state to the excited state for the F colour centre is about 5.12 eV, which corresponds to the 242-nm absorption band. These calculated results can explain the origin of the absorption bands. 相似文献