Spin filtering behaviors for a carbon chain connected with armchair- and zigzag-edged graphene nanoribbon electrodes

• So far, no work focuses on spin transport properties in carbon atomic chains sandwiched between both armchair-edged graphene nanoribbon (AGNR) and ZGNR electrodes.
• When spin polarized electrons are injected into carbon chains from ZGNR electrode, the transport channel of α-spin state is open, while β-spin channel is blocked within the bias windows. The spin polarization is thus 100%, which is ideal for spin filters.
• Moreover, we study length effects of carbon chains and find that those spin-related properties only appear for the odd number of carbon atom chains.

Using the non-equilibrium Green’s function method combined with the density functional theory, we investigate the spin transport properties of carbon chains connected with armchair- and zigzag-edged graphene nanoribbon (ZGNR) electrodes at finite bias with the parallel magnetism configuration. When spin polarized electrons are injected into carbon chains from the ZGNR electrode, the β-spin current is nearly zero, while the α-spin current shows large values in the calculated bias region, thus the spin polarization 100% can be achieved, which is a promising pathway for developing a spin filter.