Spin filtering and negative differential resistance in PAQR-ZGNR junctions

The spin transport of a Polyacene quinone radical (PAQR) molecule sandwiched between two ferromagnetic ZGNR electrodes with an even width number of 6 is studied employing the nonequilibrium Green's function method combined with the density functional theory (NEGF-DFT). Lateral symmetry mismatch of wave functions between PAQR and ZGNR may suppress all the transport channels except only one spin-down channel near the chemical potential in the linear regime. A half-metallic behavior with perfect spin filtering efficiency and strong negative differential resistance is expected. Under high bias voltage, the spin filtering efficiency changes from-100% to 90% when other transport channel is involved. Applying an external gate voltage, we can modulate greatly the conductance of the junction. These unique features are insensitive to the length of PAQR chain and suggest great application prospect for PAQR-ZGNR molecule devices.