Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 58: Poster IIb

HL 58.14: Poster

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

Nonchiral Edge States and the Chiral Metal Insulator Transition — •Stefan Kettemann1, Alexander Struck1, Bernhard Kramer1, and Tomi Ohtsuki211. Institut fuer Theoretische Physik, Uni Hamburg, Jungiusstrase 9, 20355 Hamburg — 2Sophia University , Tokyo

The quantum phase diagram of disordered quantum wires in a strong magnetic field is studied. Sharp localization transitions of chiral edge states are found. These are shown to result in zero temperature discontinuous transitions of the 2–terminal conductance between exactly integer plateau values and zero, reminiscent of first order phase transitions. This transition, the chiral metal insulator transition (CMIT)[1], is studied as function of wire width, steepness of the confinement potential and the strength and correlation length of the disorder potential. A unique state is identified at the transition, corresponding to a superposition of edge states with opposite chirality. The bulk contribution to this state is found to decrease with the increase of the wire width, characterising this state as a new state, distinguishable from the other states, existing in the quantum Hall wire [2], namely, extended edge states, 2D localised states, quasi-1-D localised states, and 2D critical states. [1] S. Kettemann, B. Kramer, T. Ohtsuki, JETP Letters 80, 316 (2004) [2] S. Kettemann, Phys. Rev. B 69, 035339 (2004).

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