Energetics of finite metallic nanowires

The size dependence of the electronic density of states, Fermi energy, and the ionization potential of a finite metallic nanowire is investigated in a free-electron model for Na and Al. a nanowire is modelled by a uniform con ductor of a finite length and a square cross-section. Simple relation betwe en the Fermi energy and the depth of a square potential well is employed wh ich yields a correct monotonic size dependence of the ionization potential. It is shown that the ionization potential as a function of the wire width, oscillates around the values provided by this average dependence. The osci llations in the energetic properties and in the elongation force result fro m the size quantization of the energy levels. (C) 2001 Elsevier Science B.V . All rights reserved.