Measurement of high electron temperatures in single atom metal point contacts by light emission

Light emission with a blackbody-like spectrum was observed during current flow through atomic-size metallic contacts formed in the scanning tunneling microscope. Within the contact, the electron temperature rises above the lattice temperature as electron-phonon energy transfer vanishes. Electron temperatures of up to 9000 K were deduced from optical spectroscopy of stable contacts. An important consequence of greatly reduced electron energy losses is that these atomic-size metal contacts have maximum current densities of similar to10(15) A m(-2), several orders of magnitude greater than for macroscopic wires. (C) 2002 American Institute of Physics.