Organic Stable Radical Oligomers as Spin Filters

Abstract

Single-molecule magnetic junctions provide versatile platforms for use in manipulating spin-polarized currents via fine-tuning the electronic properties of the sandwiched molecule. We employed the nonequilibrium Green’s function and spin-polarized density functional theory simulations to investigate the performances of high-spin organic oligoradicals as spin filters sandwiched between two gold electrodes. The spin-polarized current could be obtained using the junction bearing a high-spin molecule with almost unity spin filtering efficiency. Moreover, the spin filtering efficiency could be tuned by varying the number of magnetic units, e.g., di-, tri-, and tetraradicals. Transmission eigenchannel, spin orbital, and density of states analyses revealed how the magnetic exchange interaction in a molecule modulates the dominant electron conducting channels and spin filtering efficiency. The use of a tunable organic magnetic molecular junction system may be a promising approach in manipulating the spin-polarized currents in spintronic devices.