He原子掺杂铝材料的第一性原理研究

First-principles study of helium atom doped interstitial sites of Al

采用基于第一性原理的平面波超软赝势方法,结合广义梯度近似(GGA),计算了铝及铝晶胞间隙位置掺入He原子后体系的几何结构、电子结构、总体能量和电荷布居值.计算结果表明:随着氦在金属铝中逐渐形成,铝晶胞体系会发生晶格畸变,但总的趋势是He在铝体系的八面体位置的晶格畸变小于其在四面体位置的晶格畸变.He在铝晶胞八面体和四面体间隙的杂质形成能分别为1.3367eV和2.4411eV.由此可知,He在铝晶胞中最稳定位置是八面体间隙位置.同时,文中还从原子尺度层面分析了He原子在铝晶胞中的占位及其键合性质,讨论了铝体系引入He后对体系能带结构、态密度和价电荷密度的影响.

The geometry structure,electronic structure,total energy,Mulliken changes of He atom in the Al octahedral site and tetrahedral site were studied by first-principle plane-wave pseudopotential method and GGA. The calculation results indicated that the crystal lattice of Al was changed when He atom enter to the interstitial of Al,but the total results are the change of crystal lattice in octahedral site smaller than tetrahedral site. For Al system,the impurity formation energies of helium atom are 1. 3367 and 2. 4411 eV in the octahedral site and tetrahedral site,respectively. It is found that for He atom the best stable state is octahedral of Al. At the same time,the site occupancy and its effect of He atom in crystal cell was analysis in this article,and the effects of helium atom in Al system on band structure and density of states and valence electron density are discussed.