氧、硫掺杂六方氮化硼单层的第一性原理计算

摘要

采用基于密度泛函理论和投影缀加平面波的第一性原理计算方法，研究了六方氮化硼单层(h-BN)中的氮原子缺陷(VN)、氧原子取代氮原子(ON)和硫原子取代氮原子(SN)时的几何结构、磁性性质和电子结构。研究发现， VN和ON体系形变较小，而SN体系形变较大；h-BN本身无磁矩，但具有N缺陷或者掺杂后总磁矩都是1µB；同时给出了态密度和能带结构。利用掺杂体系的局域对称性和分子轨道理论解释了相关结果，尤其是杂质能级和磁矩的产生。%Using first-principles calculations based on density functional theory and projector augmented wave method, we investigate the geometric structures, magnetic properties and electronic structures of h-BN monolayer with nitrogen vacancy (VN), nitrogen substituted by oxygen (ON) or sulfur (SN). The results show that the h-BN monolayer with SN presents a larger geometric distortion than with ON and VN. Although the pure h-BN is non-magnetic, all the systems with defects are magnetic with the magnetization value of 1 µB per cell. Spin polarized density of states and energy band structures are presented. By using symmetrical analyses and molecular orbit theory, the formations of impurity energy levels and local magnetic moment are well explained.