On the other hand, there remains the other phase of the BNC structure, where

the positions of boron and nitrogen atoms are exchanged. To examine the effect of the phase on the spin-polarized current through www.selleckchem.com/products/r428.html the BNC structures, the transport property of the other phase of the BNC structures is investigated in this study. Therefore, our study CHIR98014 cost follows three steps: we first explore the magnetic ordering of the BNC structures under the conventional periodic boundary condition, then examine the magnetic ordering of the graphene/BNC/graphene structures, where the BNC structures are sandwiched between graphene electrodes, and finally, the spin-polarized transport property of the graphene/BNC/graphene structure is investigated. Methods All calculations are performed in the framework of the density functional theory using the real-space finite-difference approach, which makes it possible to carry out the calculation with a high degree of accuracy by combining with timesaving double-grid technique and the direct minimization of the energy functional [9–11]. The valence electron-ion interaction is described

by norm-conserving pseudopotentials [12] generated using the scheme proposed by Troullier and Martins [13]. Exchange and correlation effects are treated within the local spin density approximation [14]. In the calculation for electron transport properties, we employ the computational model in which the graphene/BNC/graphene structure

is sandwiched between the two graphene electrodes. The scattering wave functions from the left electrode are written Luminespib as follows: (1) where Φ ′s are the bulk wave functions inside the electrode and i is the index of the propagating waves from the electrode. The reflection coefficients r, transmission coefficients t, and the wave function in the scattering region ϕ are evaluated by the overbridging boundary-matching formula under the nonperiodic condition in the z direction [9, 15, 16]. The conductance under zero temperature and zero bias is described by the Landauer-Büttiker formula [17]: (2) where RAS p21 protein activator 1 T, e, and h are a transmission coefficient matrix, the electron charge, and Planck’s constant, respectively. Results and discussion Magnetic ordering of BNC structures In order to investigate the effect of the size of graphene flakes on the magnetic orderings, we first consider the three BNC structures under periodic boundary conditions for all directions. Figure 1 shows the computational models employed here, where 64 atoms are included in the supercell and the number of boron atoms is larger than that of nitrogen atoms. The number of k point used in the two-dimensional Brillouin zone integration is 16. For all the calculations in this paper, a repeating sheet model is separated by 17.0 bohr in each layer. The lattice constant is 2.67 bohr, which is obtained by the bond length of the graphene sheet.