Cyclopentadienyl-benzene based sandwich molecular wires showing efficient spin filtering, negative differential resistance, and pressure induced electronic transitions

Using density functional theory, we investigate TM-cyclopentadienyl-benzene sandwich molecular wires (SMWs) which are composites of TM-cyclopentadienyl and TM-benzene wires (TM = transition metal (V, Fe)). All the SMWs are found to be highly stable ferromagnetic half-metals, showing spin switching behavior. Transport calculations show that finite size clusters display spin filter property when coupled with Au electrodes on either side. I-V-b characteristics of all systems confirm the spin filter property, with Au-BzVCpVBz-Au displaying exceptionally high performance. In addition to spin filtering, the Au-BzFeCpFeBz-Au system also shows negative differential resistance (NDR). Compression causes an abrupt reduction in magnetic moment and a transition to a metallic phase, while stretching causes an increase in magnetic moment. Half-metallicity is preserved for modest amounts of stretching and compression.