Study of strain-induced structural, electronic, mechanical, and transport properties of one-dimensional monoatomic ultrathin gold nanowire: A DFT-NEGF approach

We conduct the first principle calculation based on Density Functional Theory (DFT) and Non-equilibrium Green Function (NEGF) approach using Generalized Gradient Approximation (GGA). We have investigated the structural, electronic, mechanical, and electronic transport properties of a one-dimensional monoatomic gold nanowire (AuNW). Plus, the influence of strain in geometrical and electronic properties also investigated. The nanowire is stable with sustainable cohesive energy of -1.52 eV. The chemical stability is due to the partly ionic and covalent bonding between the gold atoms. The electronic band shows the metallic behavior of nanowire with a conductivity of 1G0 . Furthermore, the structural and electronic properties of AuNW change significantly due to the external strain. The compressive strain decreases the bond length conversely, tensile strain increases the bond length from the equilibrium length. Similarly, the higher electronic energy states shift towards the Fermi level due to tensile strain. Furthermore, the mechanical strength of the NW is calculated by finding the tensile stiffness of the nanowire which found to be 30.31 eV/Å that is threefold less than carbyne. The transport property is studied by designing the electrode-device-electrode regime by eliminating the current quantization effect due to the contacts. We obtain the current-voltage (IV ) characteristics by varying the chemical potential in the electrode region. The current-voltage profile shows AuNW follows Ohomic current-voltage relation until current gets saturated. All these findings show that monoatomic AuNW is a potential candidate for electronic, nanomechanical, and transport applications.