论文部分内容阅读
采用基于密度泛函理论的第一性原理计算方法,研究了当氮化硼纳米管(BNNT)中的B原子和N原子被5d过渡金属原子(Lu,Hf,Ta,W,Re,Os,Ir,Pt,Au,Hg)取代时BNNT的几何结构、电子结构和磁性性质.作为对比,给出了理想BNNT,B缺陷体系(VB)和N缺陷体系(VN)的相应结果.研究发现:5d原子取代B(B5d)时体系的局域对称性接近于C3v,但是取代N(N5d)时体系的局域对称性偏离C3v对称性较大;利用相同的5d原子进行掺杂时,B5d的成键能比N5d的成键能大;对于B5d或者N5d,其成键能基本上随着5d原子的原子序数的增大而降低;掺杂体系中出现了明显的杂质能级,给出了态密度等结果;不同掺杂情况的磁矩不同,取代B时体系的总磁矩呈现出较强的规律性.利用对称性和分子轨道理论解释了5d原子取代B时杂质能级的产生和磁性的变化规律.
The first-principles calculations based on density functional theory (DFT) were used to investigate the effect of Bd and N atoms on the nucleation of 5d transition metal atoms (Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg), the electronic structures and magnetic properties of BNNTs were also compared.The results of BNNT, B defect system (VB) and N defect system (VN) The local symmetry of the system substituted by 5d atom B (B5d) is close to that of C3v, but the local symmetry deviates from C3v when N (N5d) is substituted. When the same 5d atom is used for doping, For the B5d or N5d, the bond energy decreases with the increase of the atomic number of 5d atom. The obvious impurity level appears in the doped system, Density of states, etc. The magnetic moments of different doping conditions are different, and the total magnetic moment of the system substituted for B shows a strong regularity.The symmetry and molecular orbital theory are used to explain the generation of impurity level of 5d atom instead of B Magnetic changes.