Estudo da Condutância Quântica em Fios Monoatômicos de Ouro

Abstract

The quantum conductance and the electronic structures of monoatomic gold nanowires have been studied using Density functional theory (DFT) and the Quantum-ESPRESSO open-source code. At the first moment, the monoatomic pristine gold wires were considered and relaxed to obtain a linear structure with an interatomic distance of approximately 2,38 Å. Later, calculations on the energy of the system, the respective energy bands and the density of states were performed. The above calculations demonstrated a metallic behavior of the wire. The quantum conductance of the above system was studied using the Landauer-Büttiker formalism utilizing the PWcond code of the Quantum-ESPRESSO code demonstrating a conductance of 3G_0. We also repeated the above calculations in the gold nanowire in the presence of impurities like hydrogen and aluminium. The substitution of the atoms of gold by the impurities revealed a linear structure of the nanowire. However, we observe an inhomogeneous structure leading to an increase in the bond-lengths. Moreover, we observe a decrease in the conductance of the nanowires irrespective of its conducting nature.