用XANES研究Ga_(1-x)Mn_xN稀磁半导体的Mn原子的局域结构

利用基于实空间多重散射的XANES研究了Ga1-xMnxN(x=0.01,0.25,0.10)稀磁半导体中Mn原子的局域结构.结果表明在低Mn含量(摩尔浓度)的Ga0.990Mn0.010N样品中,Mn原子替代了GaN中的Ga,以替位形式存在.当Mn含量增加到0.025时,部分Mn原子处于被4个Ga所包围的间隙位,并与替位Mn原子形成了MnGa-MnI二聚体.当Mn含量进一步增加到0.100时,样品中的Mn原子主要以Mn团簇形式存在.

The local structure of Ga_(1-x)Mn_xN dilute magnetic semiconductors determined by X-ray absorption near structure

X-ray absorption near-edge structure(XANES) spectroscopy was used to study the local structures of Mn dopants in the Ga1-xMnxN dilute magnetic semiconductors(DMS) with zinc-blende structure. The comparison between the experimental and calculated XANES spectra using the ab inito self-consistent real-space multiple-scattering approach indicates that the majority of Mn atoms are located at Ga substitutional sites MnGa in Ga1-xMnxN with the lowest(0.010) Mn content.Upon increasing the Mn content to 0.025,some of the Mn molecules occupy the interstitial sites surrounded by four Ga atoms in GaN lattice and forms MnGa-MnI dimers.At the high Mn doping concentration(0.100),Mn atoms exist primarily in the form of Mn clusters.