# Berlin 2005 – wissenschaftliches Programm

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# HL: Halbleiterphysik

## HL 58: Poster IIb

### HL 58.17: Poster

### Dienstag, 8. März 2005, 16:30–19:00, Poster TU F

**Interactions at the Integer Quantum Hall Transition** — •Christoph Sohrmann and Rudolf A. Römer — Department of Physics, University of Warwick, Coventry CV47AL, UK

Electron-electron interactions seem to play a surprisingly small role in the description of the integer quantum Hall effect, considering that for just slightly different filling factors the interactions are of utmost importance causing the interaction-mediated fractional quantum Hall effect. However, recent experiments by Cobden et al. [1] constitute strong evidence for the importance of electron-electron interactions even in the integer effect. Measurements of the conductance on mesoscopic MOSFET devices show regular patterns along the plateau transitions when viewed as a function of the two parameters magnetic field and gate voltage. In contrast to the expected random behaviour of the sample specific conductance fluctuations those patterns are most likely interaction driven and demand explanation. Starting from the random Landau matrix approach as an effective numerical model for non-interacting quantum Hall physics, we treat interactions in an approximative Hartree-Fock scheme and investigate the role of the interactions in the integer quantum Hall effect.

[1] D.H. Cobden, C.H.W. Barnes, and C.J.B. Ford, Phys. Ref. Lett. **82**, 4695 (1999)