Density functional theory study of BN-doped graphene superlattice: Role of geometrical shape and size

Abstract

Effects of geometric shape and size of embedded boron nitride (BN) nanodot on the electronic and magnetic properties of the BN-doped graphene superlattices are systematically studied by spin-polarized first-principles calculations. The band gap of graphene superlattice is found to increase with the size of the BN nanodot, regardless of the shape of BN nanodot. Midgap states are found for graphene superlattices with triangular BN nanodots, and the number of such midgap states is determined by the imbalance between the number of carbon atoms occupying A- and B-sublattices, which is closely related to the geometric shape and size of the BN nanodot. When B and N atoms in the superlattices are exchanged, the valance bands and conduction bands are inverted with respect to the Fermi level due to electron-hole symmetry. Furthermore, partial occupation of the midgap states induces spin-polarization, and results in a magnetic ground state for the BN-doped graphene superlattices with triangular BN nanodots. Through electron or hole injection, the magnetic moment of the BN-doped graphene superlattice can be tuned, which may find applications in spintronic devices.

Band gap tunning in BN-doped graphene systems with high carrier mobility

“…We find that the band gap is smaller for the multilayer than for the BN doped monolayer, bilayer, and trilayer, see Figure 2 and Table I. Following the same trend as in the other cases, the band gap increases with the BN concentration, as predicted theoretically 41 and confirmed experimentally. 33 We next turn to the electronic band structure of the superlattice in the bottom row of Figure 2.…”

Thermal conductivity of BN-C nanostructures

“…[32][33][34] For instance, Ci et al 31 have experimentally shown that decreasing the relative amount of h-BN to graphene increases the electrical conductivity, which has been supported by DFT studies where increasing BN concentration and cluster size results in band gap opening. 35,36 It is recently shown that the details of the bonding at the h-BN/graphene interface can change the type of intrinsic doping of the system. 37 Just to name a few other examples of how this chemical and structural diversity in this low dimensional hybrid system enable control over magnetic properties; zigzag-edges in ribbons have been suggested to lead to ferromagnetic behavior 38 while more complex interfaces, like those present in h-BN clusters embedded in graphene, can be antiferromagnetic 39 may also be mentioned.…”

Electronic structures and transport properties of armchair graphene nanoribbons by ordered doping

“…Recent experiments demonstrated that a largearea atomic layered thick h-BNC composite structure could be successfully fabricated [14], this indicates the possibility of B and N atom controllable doping and the formation of hybridized geometries based on graphene. For graphene composite structures related to BN-doping, the current main studies include the separate doping of B or N atoms [15], the regular doping of BN molecules [16,17], BN-chain doping [18], and the heterostructure constituted by BN nanoribbons and graphene [19], etc.…”