Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, People's Republic of China.
Phys Rev Lett. 2012 Nov 16;109(20):206802. doi: 10.1103/PhysRevLett.109.206802. Epub 2012 Nov 14.
It is highly desirable to integrate graphene into existing semiconductor technology, where the combined system is thermodynamically stable yet maintain a Dirac cone at the Fermi level. First-principles calculations reveal that a certain transition metal (TM) intercalated graphene/SiC(0001), such as the strongly bound graphene on SiC with Mn intercalation, could be such a system. Different from freestanding graphene, the hybridization between graphene and Mn/SiC leads to the formation of a dispersive Dirac cone of primarily TM d characters. The corresponding Dirac spectrum is still isotropic, and the transport behavior is nearly identical to that of freestanding graphene for a bias as large as 0.6 V, except that the Fermi velocity is half that of graphene. A simple model Hamiltonian is developed to qualitatively account for the physics of the transfer of the Dirac cone from a dispersive system (e.g., graphene) to an originally nondispersive system (e.g., TM).
将石墨烯集成到现有的半导体技术中是非常理想的，在这种技术中，组合系统在热力学上是稳定的，但在费米能级处保持狄拉克锥。第一性原理计算表明，某些过渡金属（TM）插层石墨烯/SiC（0001），例如与 Mn 插层结合的强束缚石墨烯，可能就是这样的系统。与独立的石墨烯不同，石墨烯和 Mn/SiC 之间的杂化导致主要由 TM d 特征形成的离散狄拉克锥的形成。相应的狄拉克谱仍然是各向同性的，对于高达 0.6 V 的偏压，输运行为几乎与独立的石墨烯相同，只是费米速度是石墨烯的一半。开发了一个简单的模型哈密顿量，定性地解释了从弥散系统（例如石墨烯）到原本非弥散系统（例如 TM）的狄拉克锥转移的物理性质。
