应变下氮和硼替位掺杂石墨烯的结构与电子性质

Structural and Electronic Properties of the Nitrogen and Boron Doped Graphene under Strain

采用第一性原理计算方法,研究了氮(N)和硼(B)替位掺杂石墨烯在加载应变情况下的结构和电子性质.计算结果表明(采用6×6超原胞),对于纯石墨烯,当应变大于临界应变30%时发生从弹性应变至非弹性应变的转变,体系总能在转变处发生突变.而N和B掺杂石墨烯的临界应变分别变为17.6%和17.4%,这表明掺杂石墨烯的弹性应变范围大幅减小.通过研究纯石墨烯和N/B替位掺杂石墨烯的电子性质,发现纯石墨烯在对称应变下仍为零带隙,而掺杂后费米能级处出现电子态,体系转变为金属,并且发现应变可以调节掺杂石墨烯的费米能级但不能在狄拉克锥处打开带隙.

Structural and electronic properties of the nitrogen（N）and boron（B）doped graphene under strain have been studied by the first-principles method.The results show that,the pure graphene undergoes a transition from elastic deformation to non-elastic deformation as the strain is larger than 30% with an abrupt energy drop of the system.For N doped and B doped graphene,the critical strains for the transition of elastic to non-elastic deformation are 17.6%and 17.4%respectively,indicating that the structural stability of the doped graphene is significantly reduced.For the electronic properties of the pure graphene and N/B doped graphene,we found that the pure graphene under symmetrical strain remains its zero band gap,while the N/B doped graphene changes from a semimetal to a metal with finite density of states at the Fermi level.In addition,we found that the strain can adjust the Fermi level of the doped graphene but cannot open a gap at the Dirac cone.