Matos M J S, Mazzoni M S C, Chacham H
Nanotechnology. 2014 Apr 25;25(16):165705. doi: 10.1088/0957-4484/25/16/165705.
We investigate, by means of first-principles calculations, the role of hBN point defects on the energetical stability and electronic structure of heterostructures composed of graphene atop hBN, rotated at angles of 13.17°, 9.43° and 7.34°. We consider, as possible point defects, boron and nitrogen vacancies and antisites, substitutional oxygen at the nitrogen site ON, substitutional carbon dimers, and nitrogen interstitials. The electronic and structural properties of all defects were analyzed. Among these, the most stable is ON, with negative formation energies at several possible rotation angles and chemical environments. Under such conditions, ON doping can raise the Fermi level of the neutral system by as much as 1 eV relative to graphene's Dirac point, reaching the band crossing between adjacent Dirac cones at the M point of the heterostructure Brillouin zone. This could lead to interesting electronic transport properties without the need for electrostatic doping.
我们通过第一性原理计算，研究了hBN点缺陷对由hBN上的石墨烯组成的异质结构的能量稳定性和电子结构的作用，这些异质结构以13.17°、9.43°和7.34°的角度旋转。我们考虑了硼和氮空位、反位、氮位点上的取代氧ON、取代碳二聚体以及氮间隙等可能的点缺陷。分析了所有缺陷的电子和结构性质。其中，最稳定的是ON，在几个可能的旋转角度和化学环境下具有负的形成能。在这种条件下，相对于石墨烯的狄拉克点，ON掺杂可将中性系统的费米能级提高多达1 eV，达到异质结构布里渊区M点处相邻狄拉克锥之间的能带交叉。这可能会导致有趣的电子输运性质，而无需静电掺杂。
