Eur. Phys. J. B 66, 497-501 (2008)
https://doi.org/10.1140/epjb/e2008-00458-4

Conductance through atomic point contacts between fcc(100) electrodes of gold

¹ Nanoscience Center and Department of Physics, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
² Department of Chemistry, 40014 University of Jyväskylä, 40014 Jyväskylä, Finland

Corresponding author: ^a lopez@cc.jyu.fi

Received: 11 August 2008
Revised: 28 November 2008
Published online: 18 December 2008

Abstract

Electrical conductance through various nanocontacts between gold electrodes is studied by using the density functional theory, scalar-relativistic pseudopotentials, generalized gradient approximation for the exchange-correlation energy and the recursion-transfer-matrix method along with channel decomposition. The nanocontact is modeled with pyramidal fcc(100) tips and 1 to 5 gold atoms between the tips. Upon elongation of the contact by adding gold atoms between the tips, the conductance at Fermi energy E_F evolves from G ≈ 3G₀ to G ≈ 1G₀ (G₀ = 2e/h²). Formation of a true one-atom point contact, with G ≈ 1G₀ and only one open channel, requires at least one atom with coordination number 2 in the wire. Tips that share a common vertex atom or tips with touching vertex atoms have three partially open conductance channels at E_F, and the symmetries of the channels are governed by the wave functions of the tips. The long 5-atom contact develops conductance oscillations and conductance gaps in the studied energy range -3 ≤ E-E_F ≤ 5 eV, which reflects oscillations in the local density of electron states in the 5-atom linear “gold molecule" between the electrodes, and a weak coupling of this “molecule" to the tips.