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

Abstract

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.