Magnetic and electronic properties of fluorographene sheet with foreign atom substitutions

Probes of nano scale are a type of important tools for the study on nano-film material. Dynamic explicit method accompanied by the intermittent feeding of probe to dissipate the energy is applied to avoid the difficulty of convergence in the finite element model for a system of probe, graphene, and substrate. And the results of a static state are obtained from this strategy. The functions of interface interaction forces are deduced from adhesion energy and the potential between atoms. The force functions are implanted into subroutines in Abaqus code to simulate the interactions among graphene layers, probe, and substrate. Results of simulations show good consistency with the data of experiments.

Quasi-static finite element calculation of interaction between graphene and nanoprobe

Bao-Lei¹,

Wang²,

Ke³

et al. 2014

Electronic and magnetic properties of fluorinated graphene sheets with divacancy substitutional doping

Xu¹,

Zhen-Hong²,

Sui³

et al. 2014

According to the first principles, we investigate the structure, electronic, and magnetic properties of fluorinated graphene doped with external X (Al, P, Ga, As, Si) atoms at double vacancies, and find that like double vacancy doping of graphene, this kind of the fluorinated graphene divacancy substitution is also an ideal choice for substitutional doping. The results show that the electronic property and magnetic property of the fluorinated graphene both have large changes: the fluorinated graphene doped with Al (Ga) atoms can cause the semiconductor-to-metal transitions and induce magnetic moments. The fluorinated graphene doped with P (As) atoms becomes spin-polarized semiconductor. The Si doped fluorinated graphene keeps the semiconductor properties unchanged and has no magnetic moments. Through the further discussion about the mechanism of magnetism the relation between the doping concentration and magnetic property is obtained, and the magnetic properties in different doping situations are found to be caused by the different orbital electrons of different atoms. The divacancy substitutional doping behaviors enrich not only the doping ways of fluorinated graphene materials, but also its distinctive electronic and magnetic characteristics, which make this doping structure have potential applications in future electronic devices.

Structural and electronic properties of hydrogenated bilayer silicene

Tan-Hua¹

2015

Using the density functional theory (DFT) with both the generalized gradient approximation (GGA) and HSE06 hybrid functional calculation, we have investigated the structural and electronic properties of hydrogenated bilayer silicene. Results show that the hydrogenated bilayer silicene may have three configurations: AA-chair-like, AB-chair-like and AA-boat-like forms; after hydrogenation the material properties change from zero band gap semimetal into an indirect band gap semiconductor with forbidden band widths of 1.208, 1.437, and 1.111 eV. We have performed a hybrid HSB06 functional calculation and the correction for the band gaps: 1.595, 1.785, and 1.592 eV. Further analysis of the hydrogenated bilayer silicene with a strained band gap, the relationship between strain and the band gap can be continuously adjusted. Possible applications may be found in future nano-electronic devices.