title: The enhanced spin-polarized transport behaviors through cobalt benzene-porphyrin-benzene molecular junctions: the effect of functional groups.
abstract: The modification effects of the groups amino (NH2) and nitro (NO2) on the spin polarized transport properties of the cobalt benzene-porphyrin-benzene (Co-BPB) molecule coupled to gold (Au) nanowire electrodes are investigated by the nonequilibrium Green's function method combined with the density functional theory. The calculation results show that functional groups can lead to the significant spin-filter effect, enhanced low-bias negative differential resistance (NDR) behavior and novel reverse rectifying effect in Co-BPB molecular junction. The locations and types of functional groups have distinct influences on spin-polarized transport performances. The configuration with NH2group substituting H atom in central porphyrin ring has larger spin-down current compared to that with NO2substitution. And Co-BPB molecule junction with NH2group substituting H atom in side benzene ring shows reverse rectifying effect. Detailed analyses confirm that NH2and NO2group substitution change the spin-polarized transferred charge, which makes the highest occupied molecular orbitals (HOMO) of spin-down channel of Co-BPB closer to the Fermi level. And the shift of HOMO strengthens the spin-polarized coupling between the molecular orbitals and the electrodes, leading to the enhanced spin-polarized behavior. Our findings might be useful in the design of multi-functional molecular devices in the future.
authors.affiliation: College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, People's Republic of China. School of Electronics and information engineering, Suzhou Vocational University, Suzhou 215104, People's Republic of China.
authors.forename: Jue-Fei
authors.initials: JF
authors.lastname: Cheng
authors.forename: Liping
authors.initials: L
authors.lastname: Zhou
authors.forename: Zhongqian
authors.initials: Z
authors.lastname: Wen
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yan
authors.forename: Qin
authors.initials: Q
authors.lastname: Han
authors.forename: Lei
authors.initials: L
authors.lastname: Gao