Wang Can, Wang Huaiqiang, Tian Qichao, Zong Junyu, Xie Xuedong, Chen Wang, Zhang Yongheng, Wang Kaili, Qiu Xiaodong, Wang Li, Li Fangsen, Zhang Haijun, Zhang Yi
National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China.
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China.
J Phys Chem Lett. 2022 Oct 13;13(40):9396-9403. doi: 10.1021/acs.jpclett.2c02657. Epub 2022 Oct 3.
The quantum interference patterns induced by impurities in graphene can form the (√3 × √3)R30° superlattice with intervalley scattering. This superlattice can lead to the folded Dirac cone at the center of Brillouin zone by coupling two non-equivalent valleys. Using angle-resolved photoemission spectroscopy (ARPES), we report the observation of suppression of the folded Dirac cone in mono- and bilayer graphene upon potassium doping. The intervalley coupling with chiral symmetry broken can persist upon a light potassium-doped level but be ruined at the heavily doped level. Meanwhile, the folded Dirac cone can be suppressed by the renormalization of the Dirac band with potassium doping. Our results demonstrate that the suppression of the intervalley scattering pattern by potassium doping could pave the way toward the realization of novel chiraltronic devices in superlattice graphene.
石墨烯中杂质诱导的量子干涉图案可通过能谷间散射形成（√3×√3）R30°超晶格。这种超晶格通过耦合两个不等价能谷可在布里渊区中心导致折叠狄拉克锥。利用角分辨光电子能谱（ARPES），我们报道了在钾掺杂的单层和双层石墨烯中观察到折叠狄拉克锥受到抑制。具有手性对称性破缺的能谷间耦合在低水平钾掺杂时可以持续存在，但在重掺杂水平时会被破坏。同时，折叠狄拉克锥可通过钾掺杂对狄拉克能带的重整化而受到抑制。我们的结果表明，钾掺杂对能谷间散射图案的抑制可为在超晶格石墨烯中实现新型手性电子器件铺平道路。
