Large modulation-amplitude, local barrier-height, scanning tunneling microscopy
Department of Physics, The Pennsylvania State
University University Park, PA 16802, USA
Accepted: 23 March 2001
We compare and contrast both STM topographic images and local tunneling barrier-height (LBH) spatial distributions using relatively large modulation of the tunneling gap. Measurements were carried out on various surfaces including -, --, --. The experimental results of the local barrier-height obtained in this way are dependent on the tip-sample distance indicative of strong tip-sample interaction. The large modulation LBH method senses the "hardness"of the tip surface interaction potential, which varies with lattice position. Both methods, STM topographic images and local barrier-height images, provide complementary, but different information, to check the consistency of structural conclusions.
PACS: 68.37.Ef – Scanning tunneling microscopy (including chemistry induced with STM) / 68.35.Bs – Structure of clean surfaces (reconstruction) / 81.05.-t – Specific materials; fabrication, treatment, testing and analysis
© EDP Sciences, 2001