掺杂三角形硼氮片的锯齿型石墨烯纳米带的磁电子学性质

Magneto-electronic properties of zigzag graphene nanoribbons doped with triangular boron nitride segment

利用基于密度泛函理论的第一性原理方法,研究了三角形BN片掺杂的锯齿型石墨烯纳米带(ZGNR)的磁电子学特性.研究表明:当处于无磁态时,不同位置掺杂的ZGNR都为金属;当处于铁磁态时,随着杂质位置由纳米带的一边移向另一边时,依次可以实现自旋金属-自旋半金属-自旋半导体的变化过程,且只要不在纳米带的边缘掺杂,掺杂的ZGNR就为自旋半金属;当处于反铁磁态时,在中间区域掺杂的ZGNR都为自旋金属,而在两边缘掺杂的ZGNR没有反铁磁态.掺杂ZGNR的结构稳定,在中间区域掺杂时反铁磁态是基态,而在边缘掺杂时铁磁态为基态.研究结果对于发展基于石墨烯的纳米电子器件具有重要意义.

In this paper, magneto-electronic properties of zigzag graphene nanoribbons（ZGNR） doped with triangular boron nitride（BN） segments are investigated by using first-principles method based on density functional theory. It is shown that in the nonmagnetic state, the ZGNRs doped with triangular BN segments at different positions are metals. In the ferromagnetic state, with the impurities moving from one edge of the nanoribbon to the other edge, a transition is caused from a spin metal to a spin half-metal, and then to spin semiconductor, and as long as the impurity is not on the edge of the nanoribbon, the doped ZGNR is always spin half-metal. In the antiferromagnetic state, the ZGNR doped in the middle of the nanoribbon is spin metal, while the ZGNR doped on the edge of the nanoribbon has no antiferromagnetic state. The electronic structures of the ZGNRs doped with BN segments at different positions are explained by the difference in charge density. The binding energies of doped ZGNRs are negative, thus the structures of the doped ZGNRs are stable. As the impurity moves from position P1 to position P5, the binding energy decreases gradually. When the impurity is located at position P5, the binding energy of ZGNR is smallest, and the structure of ZGNR is most stable. When the impurity doped in the middle of the nanoribbon, the antiferromagnetic state is the ground state, while the impurity is doped on the edge of the nanoribbon, the ferromagnetic state is the ground state.These obtained results are of significance for developing electronic nanodevices based on graphene.