Hydrogen Doping-Enriched Geometric and Electronic Properties of Pristine Graphene
Tran Ngoc Thanh Thuy1*, Lin Ming-Fa1
1Department of Physics, National Cheng Kung University, Tainan, Taiwan
* Presenter:Tran Ngoc Thanh Thuy
The essential properties of hydrogenated graphenes with various concentrations and distributions are investigated by the first-principles calculations in detail. The geometric structures strongly depend on the significant H-C bonds and the curvature-induced hybridizations in C-C bonds, and so do the electronic properties. The planar structure is changed into the buckled one, leading to the sensitive changes in bond lengths, bond angles and carbon heights. There exist middle, narrow and zero energy gaps even at high adatom concentrations. Furthermore, whether ferromagnetic spin configurations could survive is mainly determined by the adatom distributions. The band structures display the rich features, including the destruction or recovery of the Dirac-cone structure, critical points, weakly dispersive bands, and (C,H)-related partially flat bands. The orbital-projected density of states are clearly marked by the low-energy prominent peaks, delta-function-like peaks, discontinuous shoulders, and logarithmically divergent peaks. By the detailed analyses, the strong competitions in the critical chemical bondings of sp3s and sp2 are responsible for the diverse properties. In general, hydrogenated graphenes exhibit tunable band gaps as well as ferromagnetism, and they are potential candidates for hydrogen storage applications.

Keywords: Graphene, hydrogen, electronic, first-principles