DESIGN, OPERATION, AND HOUSING OF AN ULTRASTABLE, LOW-TEMPERATURE, ULTRAHIGH-VACUUM SCANNING TUNNELING MICROSCOPE

We have designed and constructed a low temperature, ultrahigh vacuum s canning tunneling microscope (STM), taking extreme measures to isolate the microscope from acoustic, vibrational, and electronic noise. We c ombined a 4 K STM with line-of-sight dosing to enable one to position the crystal surface in front of an impinging molecular beam as in scat tering experiments. Due to the mechanical stability of the instrument and the minimal thermal drift associated with working at 4 K we are ab le to locate and to image repeatedly isolated adsorbates and atomic-sc ale structures, such as step edges, for extended periods days. The ins trument has been designed for the topographic and spectroscopic charac terization of atoms and molecules on metal and semiconductor surfaces, for the investigation of the mechanism by which the STM images adsorb ates on surfaces, and for inelastic electron tunneling spectroscopy of single molecules. (C) 1998 American Institute of Physics. [S0034-6748 (98)00507-3]