▎ 摘　　要

By omitting some carbon atoms from middle of a zigzag graphene cluster, and Hydrogen termination of sp(2) orbital, we make the different porous zigzag graphene clusters, and investigate the electron transport properties of the structures by the non-equilibrium Green function method at zero bias regime. It is shown that, the conductance of porous clusters depends on the final symmetry of porous cluster and the local imbalance number (n(A) - n(B)), in which n(A) and n(B) are the number of omitted atoms from A-sublattice and B-sublattice respectively. Also it is shown that, if three carbon atoms (one type-A and two type-B sites) are omitted the conductance for vertical bar E-E-f vertical bar >= 5 eV is significantly higher than the conductance of original zigzag graphene cluster due to the increment in less affected conducting channels. We show that, spin flipping occurs under Rashba spin orbit interaction at E=E-f, when three atoms are omitted from the original cluster. Therefore the local imbalance number and final symmetry of porous graphene cluster can be used as a rule for designing porous graphene devices and the device can be used in spintronic applications. (C) 2013 Elsevier B.V. All rights reserved.