9502920 Valles This experimental project involves low temperature scanning tunneling microscopy and electron magneto-transport and tunneling measurements on strongly disordered ultrathin films. The experiments will investigate the physical effects behind the profound and sometimes spectacular changes (e.g.,the superconductor to insulator transition) that occur in electronic systems in the strongly disordered limit in two dimensions. The ultra-thin metal films are fabricated in situ by thermal evaporation of the constituent metals onto substrates held at temperatures near 4 K. Experiments with the scanning tunneling microscope will measure the atomic surface structure as well as variations in their local tunneling density of states. The experiments are of interest from fundamental viewpoints, as well as technical viewpoints, as the results will increase our understanding of electronic conduction processes in metals. %%% This experimental project involves low temperature scanning tunneling microscopy and electron magneto-transport and tunneling measurements on strongly disordered ultrathin films. The experiments will investigate the physical effects behind the profound and sometimes spectacular changes (e.g., the superconductor to insulator transition) that occur in electronic systems in the strongly disordered limit in two dimensions. The ultra-thin metal films are fabricated in situ by thermal evaporation of the constituent metals onto substrates held at temperatures near 4 K. Experiments with the scanning tunneling microscope will measure the atomic surface structure as well as variations in their local tunneling density of states. The experiments are of interest from fundamental viewpoints, as well as technical viewpoints, as the results will increase our understanding of electronic conduction processes in metals. ***
