应变和C掺杂对单层BN纳米片的电子结构和磁学性质的影响

摘要

Using the first principles based on density of functional theory (DFT), the effects of strain and C dopant on the electronic structure and magnetic property of single layer BN nanosheet were studied. The calculated results indicated that the BN nanosheet is of wide band gap which can be widen and decreased under compressive and tensile strain, respectively, while the effect of strain on band gap is not significant. The density of states (DOS) indicated that the single C-doped BN nanosheet shows half-me-tallicity, and the magnetic moment is mainly contributed by C 2p states, and the B 2p and N 2p states also has little contribution. The magnetic ground state for double C-doped BN nanosheet can be tuned by the variation of distance between two C atoms: the antiferromagnetic state is the ground state when the distance is shorter (the nearest neighbor and the next nearest neighbor), while the stable state change to ferromagnetic state as the double C atoms has a relatively longer distance (the next next nearest neighbor) and then the half-metallicity is also presented.%利用基于密度泛函理论的第一性原理计算方法,研究了应变和C原子掺杂对单层BN纳米片的电子结构和磁学性质的影响.计算结果表明未掺杂的单层BN纳米片具有宽的直接带隙,在压缩和拉伸应变的作用下,带隙会分别增大和减小,但应变对带隙的调制整体效果不太明显.单个C原子掺入BN纳米片的态密度揭示体系呈现出半金属性(Half-metallicity),磁矩主要源于C2p态,而B 2p和N 2p态在极化作用下也能提供部分磁矩.两个C原子掺入BN纳米片时,磁性基态会随着C原子的间距发生变化:当两C原子为最近邻(nn)和次近邻(nnn)时,反铁磁态为磁性基态；而当两C原子为次次近邻(nnnn)时,铁磁态为基态,并且其态密度也显示出半金属性.