Electronic structure effects on stability and quantum conductance in 2D gold nanowires
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In this study, we have investigated the stability and conductivity of unsupported, two-dimensional infinite gold nanowires using ab initio density functional theory (DFT). Two-dimensional ribbon-like nanowires with 1–5 rows of gold atoms in the non-periodic direction and with different possible structures have been considered. The nanowires with >2 rows of atoms exhibit dimerization, similar to finite wires, along the non-periodic direction. Our results show that in these zero thickness nanowires, the parallelogram motif is the most stable. A comparison between parallelogram- and rectangular-shaped nanowires of increasing width indicates that zero thickness (111) oriented wires have a higher stability over (100). A detailed analysis of the electronic structure, reveals that the (111) oriented structures show increased delocalization of s and p electrons in addition to a stronger delocalization of the d electrons and hence are the most stable. The density of states show that the nanowires are metallic and conducting except for the double zigzag structure, which is semiconducting. Conductance calculations show transmission for a wide range of energies in all the stable nanowires with more than two rows of atoms. The conductance channels are not purely s and have strong contributions from the d levels, and weak contributions from the p levels.
Keywords2D nanowires Au Conductivity Electronic structure calculations Density functional theory Quantum effects Modeling and simulation
This study was performed using BARC mainframe supercomputers (ajeya and ameya). The authors thank Dilip G Kanhere and Stefan Blügel for their stimulating discussions. V. S. would like to thank Dept. of Science and Technology, Govt. of India for their funding support. V.K. thanks BARC for financial support. V. K. and V. S. wish to thank the kind hospitality of Bioinformatics Center, University of Pune and Institute of Bioinformatics and Biotechnology, University of Pune, during the course of this study.