Abstract
We investigate the elongation and breaking process of metallic nanowires using the ultimate jellium model in self-consistent density-functional calculations of the electron structure. In this model the positive background charge deforms to follow the electron density and the energy minimization determines the shape of the system. However, we restrict the shape of the wires by assuming rotational invariance about the wire axis. First we study the stability of infinite wires and show that the quantum mechanical shell-structure stabilizes the uniform cylindrical geometry at given magic radii. Next, we focus on finite nanowires supported by leads modeled by freezing the shape of a uniform wire outside the constriction volume. We calculate the conductance during the elongation process using the adiabatic approximation and the WKB transmission formula. We also observe the correlated oscillations of the elongation force. In different stages of the elongation process two kinds of electronic structures appear: one with extended states throughout the wire and one with an atom-cluster like unit in the constriction and with well localized states. We discuss the origin of these structures.
Highlights
The miniaturization of the electronic components is of great importance in the development and improvement of new devices for applications in a wide number of fields
We investigate the elongation and breaking process of metallic nanowires using the ultimate jellium model in self-consistent density-functional calculations of the electronic structure
II, we describe the practical features of the UJ model and the RQMG method to calculate the electronic structure during the elongation process
Summary
The miniaturization of the electronic components is of great importance in the development and improvement of new devices for applications in a wide number of fields. The laws of nature are the same for macroscopic and mesoscopic systems, the miniaturization process is achieving the limit where the quantum behavior of matter starts to play an important role. The regime of quantum behavior is reached if one of the spatial dimensions of the system is reduced down to the Fermi wavelength of the conducting electrons. The confinement splits the continuous electronic band in this direction into a set of discrete energy levels. In both cases, the behavior of the system changes from what is expected from the macroscopic case. In metallic nanowires the Fermi wavelength is of the same order of magnitude as the atomic distance, and both atomic and electronic discrete character compete and/or couple, determining the properties of nanowires
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