Quantum conductance of silicon-doped carbon wire nanojunctions
1 Institute for Molecules and Materials UMR 6283, University of Maine, Ave. Olivier Messiaen, Le Mans, 72085, France
2 Institute of Physics, Jan Długosz University in Czȩstochowa, Al. Armii Krajowej 13/15, Czȩstochowa, 42200, Poland
3 Institute of Physics, Czȩstochowa University of Technology, Al. Armii Krajowej 19, Czȩstochowa, 42200, Poland
4 Department of Physics, Texas A&M University, Education City, PO Box 23874, Doha, Qatar
Nanoscale Research Letters 2012, 7:616 doi:10.1186/1556-276X-7-616Published: 7 November 2012
Unknown quantum electronic conductance across nanojunctions made of silicon-doped carbon wires between carbon leads is investigated. This is done by an appropriate generalization of the phase field matching theory for the multi-scattering processes of electronic excitations at the nanojunction and the use of the tight-binding method. Our calculations of the electronic band structures for carbon, silicon, and diatomic silicon carbide are matched with the available corresponding density functional theory results to optimize the required tight-binding parameters. Silicon and carbon atoms are treated on the same footing by characterizing each with their corresponding orbitals. Several types of nanojunctions are analyzed to sample their behavior under different atomic configurations. We calculate for each nanojunction the individual contributions to the quantum conductance for the propagating σ, Π, and σ∗electron incidents from the carbon leads. The calculated results show a number of remarkable features, which include the influence of the ordered periodic configurations of silicon-carbon pairs and the suppression of quantum conductance due to minimum substitutional disorder and artificially organized symmetry on these nanojunctions. Our results also demonstrate that the phase field matching theory is an efficient tool to treat the quantum conductance of complex molecular nanojunctions.