Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
Nanotechnology. 2011 Jul 8;22(27):275704. doi: 10.1088/0957-4484/22/27/275704. Epub 2011 May 20.
The atomic and electronic structures of an Au-intercalated graphene monolayer on the SiC(0001) surface were investigated using first-principles calculations. The unique Dirac cone of graphene near the K point reappeared as the monolayer was intercalated by Au atoms. Coherent interfaces were used to study the mismatch and the strain at the boundaries. Our calculations showed that the strain at the graphene/Au and Au/SiC(0001) interfaces also played a key role in the electronic structures. Furthermore, we found that at an Au coverage of 3/8 ML, Au intercalation leads to a strong n-type doping of graphene. At 9/8 ML, it exhibited a weak p-type doping, indicative that graphene was not fully decoupled from the substrate. The shift in the Dirac point resulting from the electronic doping was not only due to the different electronegativities but also due to the strain at the interfaces. Our calculated positions of the Dirac points are consistent with those observed in the ARPES experiment (Gierz et al 2010 Phys. Rev. B 81 235408).
使用第一性原理计算研究了 SiC(0001)表面上 Au 嵌入石墨烯单层的原子和电子结构。单层被 Au 原子嵌入后，石墨烯在 K 点附近独特的狄拉克锥再次出现。使用相干界面研究了边界处的不匹配和应变。我们的计算表明，石墨烯/Au 和 Au/SiC(0001)界面处的应变也对电子结构起着关键作用。此外，我们发现，在 Au 覆盖率为 3/8 ML 时，Au 嵌入导致石墨烯的强烈 n 型掺杂。在 9/8 ML 时，它表现出较弱的 p 型掺杂，表明石墨烯并未完全与衬底解耦。电子掺杂引起的狄拉克点位移不仅归因于不同的电负性，还归因于界面处的应变。我们计算的狄拉克点位置与 ARPES 实验（Gierz 等人，2010 年，Phys. Rev. B 81，235408）观察到的位置一致。
