Imaging Transport Resonances in the QHE
High resolution Images
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Presentations are in PDF format or in Powerpoint 2003 format.
- Contributed Talk presented by G. A. Steele at EP2DS-16 in Albuquerque, NM, July 2005. This presentation has several extra slides at the end, including data at different filling factors and an alternative explanation of our earlier results on topographic mapping of the quantum Hall liquid using a few-electron bubble
- A short talk presented by G. A. Steele at the APS March Meeting in L.A. in 2005
- A long talk presented by R. C. Ashoori at a conference at the University of Minnesota
The following are in uncompressed avi format.
|Movies showing the evolution of 5x5 um in-phase and lagging-phase scans with bias voltage at 4.8T. Tip voltage is stepped from -0.25 to 1.55V in steps of 0.2V. At a critical voltage, the hole bubble forms, and then continues to grow as the voltage is increased.|
|More hole-bubble movies showing the evolution of a 10x10 um in-phase and lagging-phase scan with bias voltage at 5.5T. Tip voltage is stepped from -0.35 to 1.65V in steps of 0.1V.|
|Electron-bubble movies showing the evolution of a 5x5 in-phase and lagging-phase scan with bias voltage at 8T. Tip voltage is stepped from -3.25 to +1.25V in steps of 0.2V.|
A movie showing the evolution of the density profile as the tip is scanned, as calculated in our simulations. The bulk filling factor is 0.8 and the tip bias is chosen to produce a local filling factor of 1.3 under the tip. The blue color scale represent local densities of ν 1. .
The simulation includes an approximate model of donor correlations from Efros, Pikus, and Samsonidze, Phys. Rev. B 41 8295 (1990). We have used the non-equilibrium model with a Ceff of 1.5x1010 e/cm2.