CONDUCTANCE CALCULATIONS FOR THE ATOMIC RELAY

The resistance of a wire consisting of a line of 3 Mg atoms between tw o macroscopic metallic electrodes is calculated as a function of the d isplacement of the center atom laterally out of the line. A displaceme nt of somewhat over 3 Angstrom increases the resistance by a factor of similar to 10. This contrasts with the behavior of open-shell atoms: a lateral displacement of the same magnitude of the central atom in a line of Na atoms leads in fact to a small decrease in resistance. (C) 1998 Academic Press Limited.