Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 18: Symposium: Physics in High Magnetic Fields
HL 18.6: Fachvortrag
Dienstag, 12. März 2002, 17:00–17:30, H15
High magnetic fields in semiconductor nanostructures — •U. Zeitler1, I. Hapke-Wurst1, H. Frahm2, R. J. Haug1, K. Pierz3, and A. G. M. Jansen4 — 1Institut für Festkörperphysik, Universität Hannover, Appelstraße 2, D-30167 Hannover — 2Institut für theoretische Physik, Universität Hannover — 3PTB Braunschweig, 38116 Braunschweig — 4Grenoble High Field Magnet Laboratory, MPIF-CNRS, Grenoble, France
The influence of high magnetic fields to semiconductor nanostructures can lead to spectacular field induced effects. In this talk we will present two prominent examples.
In the first part we will show how an in-plane magnetic field applied to the two-dimensional electron system of a Si/SiGe heterostructure induces pronounced transport anisotropies in the magnetoresistance [1]. We will propose that these anisotropies can be explained by the formation of a unidirectional stripe phase oriented perpendicular to the in-plane field.
The second part of the talk will be devoted to magnetic field induced Fermi edge singularities observed in the resonant tunnelling through self-assembled InAs quantum dots [2]. Current steps in the I-V-characteristics assigned to single electron tunnelling evolve into extremely enhanced current peaks in high magnetic fields (B>20 T). The singularity will be shown to be due to the Coulomb interaction between the tunnelling electron on the quantum dot and the partly spin-polarized Fermi sea in the Landau quantized three-dimensional emitter.
[1] U. Zeitler et al., Phys. Rev. Lett. 86, 866 (2001).
[2] I. Hapke-Wurst et al., Phys. Rev. B. 62, 12621 (2000).