Electric Field Induced Phenomena in STM: Tip Deformation and Au(111)- Surface Phase Transitions during Tunneling Spectroscopy Experiments
Abstract
We report electric field induced phase transitions of Au(111) surfaces and electric field stress induced elongations of Pt-Ir and Au tips during current voltage measurements with an STM in air. Transitions between the reconstructed square root of 3 x 22 and the unreconstructed 1x1 phase of the Au(111) surface are attributed to changes in the electronic surface excess charge density induced by the electric field between tip and sample. Elongations of STM tips during tunneling spectroscopy give rise to a distinct non-linear current-voltage response at tip-to-sample biases greater than approx. absolute value of 0.5Vl. Similar behaviour is observed during tunneling measurements on pyrolytic graphite and oxidized Ag surfaces. Extensive elongations can result in tip-sample point-contact and tip-fracture. Artificially low values of the apparent barrier height are shown to result from tip elongation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 20, 1993
- Accession Number
- ADA262208
Entities
People
- Henry S. White
- Joachim H. Schott
Organizations
- University of Minnesota