Atomic scale variation of tunneling current noise on GaAs(110) measured by scanning tunneling microscopy

The spatial distribution of tunneling current fluctuations occurring in a scanning tunneling microscope is measured on GaAs(110). For the first time noise patterns are shown exhibiting a commensurate structure on atomic scale. On clean GaAs(110) we find increased noise at the position of the Ga atoms while either the Ga atoms or the As atoms are visible in the topography depending on the polarity of the tunneling voltage. The noise is of 1/f‐type. We propose that the noise enhancement is caused by the statistics of a specific optical surface phonon leading to a very large vibrational amplitude of the outermost Ga atoms.