Electron Transport in Stretched Monoatomic Gold Wires

The conductance of monoatomic gold wires containing 3–7 gold atoms has been obtained from ab initio calculations. The transmission is found to vary significantly depending on the wire stretching and the number of incorporated atoms. Such oscillations are determined by the electronic structure of the one-dimensional (1D) part of the wire between the contacts. Our results indicate that the conductivity of 1D wires can be suppressed without breaking the contact.

Figure 1

Zero-bias transmission $T(E=0,L)$ through the gold chains consisted of $N=3,\dots ,7$ atoms connected to two Au(111) surfaces (top) and binding energies for the corresponding infinite chains (bottom). The total transmission (shown in blue) is decomposed into the sum ($T=T_1+\sum _{i>2}{T}_i$) of the largest eigenchannel ($T_1$) (red) and the remaining contributions ($\sum _{i>2}{T}_i$) (green). Red bars (shown in both panels) indicate the interval of 1D chain existence. For the wires marked by red dots and numbered from 1 ($L_1$) to 6 ($L_6$), the calculated transport density at the Fermi level is shown in gray in arbitrary units; the corresponding energy dependence is shown in Fig. 2.

Figure 2

Zero-bias transmission of the wires with $N=5$ (left) and $N=6$ (right) on the energy-length plane. The intensities of the transmission peaks are according to the scale on the right. Average transport densities of states ($G_C{\Gamma }_R{G}_C^{+}$) for the wires $L_{1,2,3}$ (left) and $L_{4,5,6}$ (right) (see Fig. 1) are shown decomposed into $s+d_{z^2}$ (black), $d_{zx}$ (green), and $d_{zy}$ (blue) contributions. The high density peaks below $E_F$ are truncated.

Figure 3

PDOS of the wire connected to two Au(111) gold surfaces for $N=5$ (top) and $N=6$ (bottom). Structures in the insets represent wire configurations at $L_{1,\dots ,6}$ stretching (see Fig. 1). The corresponding transmission spectrum is shown overlapped with $p$ states (red line). Shown band structure for $L=L_2,L_5$ is calculated within the supercell approach.