Magnetism and spin transport of carbon chain between armchair graphene nanoribbon electrodes

• Spin-polarized transmission in carbon chain junction without any magnetic field.
• Fully spin polarized current near the Fermi energy in all odd-numbered carbon chain.
• Energy gap and magnetic distribution depend on the position of the carbon chains.
• Spin transport properties depend on the position and the length of the carbon chains.

The magnetic and spin transport properties of a carbon chain between two armchair graphene nanoribbon (AGNR) electrodes were studied using tight-binding Hamiltonian, mean-field Hubbard model and Landauer–Butikker formalism. The results showed that only odd-numbered carbon chains show intrinsic magnetic moments in chain–graphene junctions. It was also found that the electronic, magnetic and spin transport properties of carbon chain–graphene junctions strongly depend on the position and the length of the carbon chains between AGNR electrodes. Interestingly, we found a fully spin-polarized transmission near the Fermi energy in all odd-numbered carbon chain–graphene junctions, regardless of their lengths and without any magnetic field and magnetic electrodes.