Mg掺杂AlN的磁性

Magnetism of Mg-doped AlN

采用基于密度泛函理论(Density function theory,DFT)的第一性原理方法,计算研究了AlN中掺杂Mg后的电子结构和磁性。我们从理论上给出了AlN∶Mg的晶体结构参数和电子结构,计算了铁磁相和反铁磁相的总能,发现AlN∶Mg具有半金属特性,并且其铁磁相更稳定。我们通过分析比较AlN和AlN∶Mg的电子结构,解释了非磁性杂质Mg掺杂在AlN中产生磁性的原因是Mg取代Al后,会在自旋向下的价带顶部引入空穴,导致费米能级移入价带中,从而使自旋向上和自旋向下的态密度产生不对称的分布,从而导致材料中有净磁矩。另外,通过比较AlN∶Mg的多种构型的形成能,发现在纤锌矿结构AlN中掺入Mg比较容易实现,在闪锌矿结构中次之,但对于其它几何构型,由于形成能太高,Mg很难掺入到材料中。这种材料可作为制备非磁性掺杂的半导体自旋电子器件的备选材料。

Using first principles calculations based on density function theory,we studied the magnetism of Mg-doped AlN.We found that AlN∶Mg is a half-metal and a ferromagnet.We explained that the origin of ferromagnetism is due to the holes introduced by doping Mg and the asymmetry of state density of spin-up and spin-down.Based on the analysis of formation energy,we find that it is possible to prepare Mg-doped AlN.AlN∶Mg could be useful in spintronics.