Hamburg 2001 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 7: Poster I
HL 7.44: Poster
Montag, 26. März 2001, 10:30–19:00, Rang S\ 3
Magnetotransport in 1d short-period lateral superlattices — •Michael Langenbuch, Roland Onderka, Michael Suhrke, and Ulrich Rössler — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Deutschland
Magnetotransport studies on two-dimensional electron systems (2DES) subjected to a lateral periodic electrostatic potential provide information about the physics of Bloch electrons in a magnetic field.
Besides the well-known Shubnikov-de Haas oscillations for the homogeneous electron system the magneto-conductivity of the modulated system exhibits additional characteristic low-field 1/B oscillations. For large lattice constants (compared to the Fermi wavelength λF) commensurability oscillations show up, which can be understood in a classical picture. For smaller lattice constants (in the order of λF) new 1/B periodic oscillations have been observed recently and ascribed to quantum effects arising from the band structure. We have studied these effects in more detail by calculating the magnetoresistance of a 2DES subjected to a one-dimensional electrostatic modulation using both the quantum mechanical Kubo formula and semiclassical linear response theory. The latter has the advantage of providing an intuitive picture of quantum effects in the electron dynamics based on classical orbits.
In both methods we find a variation in the amplitude of quantum oscillations which we can ascribe to drifting cyclotron orbits.