title: Transport properties of binuclear metal complexes of the VIII group using a simplified NEGF-DFT approach.
abstract: We report on a theoretical study of the electronic transport properties of binuclear complexes of metals of the VIII group bridged by pyrazine. Metal-porphyrazine units have been combined in order to investigate symmetric and non-symmetric species with particular focus on their current rectification properties. Transmission functions and I-V characteristics of the various species have been computed using a Non-Equilibrium Green Function with a simplified treatment of the molecule-lead interaction. The results obtained show an overall moderate asymmetry in the current along the molecules, which is of the donor-σ-acceptor type and follow the trend of the ionization potential of the metals in the binuclear system. The bias-dependent rectification ratio, which is significant in a limited voltage window, can be explained in terms of the alignment of the occupied orbitals of the metallic fragments that contribute to the HOMO and HOMO - 1 of the supermolecule. The possible improvement of the rectification performance of such a class of molecules has also been investigated exploiting suitable substitution by electron-withdrawing groups.
authors.affiliation: Scuola Normale Superiore, Piazza dei Cavalieri, I-56126 Pisa, Italy. vincenzo.barone@sns.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
authors.forename: Ivo
authors.initials: I
authors.lastname: Cacelli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ferretti
authors.forename: Michele
authors.initials: M
authors.lastname: Visciarelli
mesh_terms: D007501:Iron / Q000737:chemistry; D008024:Ligands; D008665:Metalloporphyrins / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D009992:Osmium / Q000737:chemistry; D011719:Pyrazines / Q000737:chemistry; D011789:Quantum Theory; D012428:Ruthenium / Q000737:chemistry
chemical_list: D008024:Ligands; D008665:Metalloporphyrins; D009942:Organometallic Compounds; D011719:Pyrazines; D009992:Osmium; D012428:Ruthenium; D007501:Iron