Ab initio study of half-metallicity and magnetism of complex organometallic molecular wires

Our ab initio calculations show that half-metallicity can be readily achieved in complex transition metal-cyclopentadienyl TM′-TM _nCp_n+1 sandwich molecular wires (SMWs). The half-metallicity and ferromagnetism/antiferromagnetism of complex SMWs are found to originate from the coupling between d electrons of TM and TM′ atoms via the ligands, which determines the filling of the d bands of TMs. A general "competitive charger-transfer" model is proposed to predict the half-metallicity in complex TM′-TM_nCp_n+1 SMWs. Furthermore, a series of robust half-metallic ferromagnets, as well as a narrow gap antiferromagnet, are identified using ab initio calculations combined with the model analysis. With tunable electronic and magnetic properties, complex SMWs have profound applications in spintronic devices.