Composite fermions in a weakly density modulated 2DEG: direct evidence of a periodic magnetic field around nu=1/2

Jobst, S and Zwerschke, S and Smet, JH and Gerhardts, RR and Weiss, D and von Klitzing, K and Umansky, V (2000) Composite fermions in a weakly density modulated 2DEG: direct evidence of a periodic magnetic field around nu=1/2. PHYSICA E, 6 (1-4). pp. 87-90. ISSN 1386-9477,

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Abstract

We investigate the magnetoresistance of a weakly density modulated high mobility two-dimensional electron system around filling factor v = 1/2. The density modulation with periods a between 300 nm and 500 nm was generated by in situ interferometric illumination. At low B we found commensurability oscillations of the magnetoresistance characteristic for transport in weak electrostatic potentials with minima positions on the magnetic field axis given by 2R(C) = (lambda - 1/4)a. Here 2R(C) is the electron cyclotron diameter at the Fermi-energy and lambda an integer. In contrast, we find clear magnetic commensurability features around filling factor v = 1/2 with a pronounced minimum for a composite fermion cyclotron radius R-C,R-CF matching 1.25a. This gives direct evidence that the density modulation results in a modulated effective magnetic field for composite fermions. The experimental rho(xx)-traces around v = 1/2 are well described by novel model calculations, based on a semiclassical solution of the Boltzmann equation, taking into account anisotropic scattering. (C) 2000 Elsevier Science B.V. All rights reserved.

Item Type: Article
Uncontrolled Keywords: DIMENSIONAL ELECTRON-GAS; MAGNETORESISTANCE; OSCILLATIONS; FQHE; composite fermions; modulated 2DEGs
Subjects: 500 Science > 530 Physics
Divisions: Physics > Institute of Experimental and Applied Physics > Chair Professor Weiss > Group Dieter Weiss
Depositing User: Dr. Gernot Deinzer
Date Deposited: 21 May 2021 06:47
Last Modified: 21 May 2021 06:47
URI: https://pred.uni-regensburg.de/id/eprint/42871

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