Electron transport and phonons in atomic wires

A scanning tunnelling microscope (STM) at low temperatures is used to fabricate and measure the electronic transport properties of atomic wires up to 7 atoms in length. We observe that the conductance of these wires, which at zero bias voltage is 2e(2)/h, as corresponds to ballistic electron transport through a single conductance quantum channel, drops sharply at a well-defined voltage due to the inelastic scattering of electrons with phonons. This behaviour is characteristic of one-dimensional systems, where an electron can interact only with a phonon of a well-defined wavenumber. We find that the frequency of this phonon and the magnitude of the interaction depend strongly on the state of strain of the wire. We also explore the energy exchange mechanism between electrons and phonons in the wire itself which causes heating in these nanostructures. (C) 2002 Elsevier Science B.V. All rights reserved.