Efficient spin filter based on FeN4 complexes between carbon nanotube electrodes

We present a theoretical study to explore the spin transport properties of FeN4 complexes sandwiched between two armchair (5, 5) carbon nanotube (CNT) electrodes. The ab initio modeling is performed by combining the spin-dependent density functional theory with nonequilibrium Green's function formalism. The calculated results clearly demonstrate that the transport properties of FeN4 complexes are sensitive to the contact configuration. Near the Fermi level the conductance through three examined junctions is mainly governed by the spin-up electrons. The FeN4 complex coupled to CNT electrodes with the pi-type contact conjugation can act as a nearly perfect spin filter, and its spin filter efficiency is up to 98.0%. Our theoretical results demonstrate that FeN4 complexes are promising for future molecular spintronics devices.