Volume 94, Number 3, May 2011
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||27 April 2011|
Fractional quantum Hall effect in second subband of a 2DES
Departamento de Física, Universidade Federal do Paraná - CP 19044, CEP 81531-990, Curitiba, PR, Brazil
2 Instituto de Física, Universidade Federal de Alagoas - 57072-970, Alagoas, Brasil
3 Instituto de Física da Universidade de São Paulo - CP 66318, CEP 05315-970, São Paulo, SP, Brazil
4 Institute of Semiconductor Physics - Novosibirsk, 630090, Russia
5 GHMFL-CNRS - BP-166, F-38042 Grenoble Cedex 9, France, EU
6 INSA-Toulouse - F-31077 Toulouse Cedex 4, France, EU
7 Institut Universitaire de France - Toulouse, France, EU
Accepted: 26 March 2011
In the present paper we report on the experimental electron sheet density vs. magnetic field diagram for the magnetoresistance Rxx of a two-dimensional electron system (2DES) with two occupied subbands. For magnetic fields above 9 T, we found fractional quantum Hall levels centered around the filing factor ν=3/2 in both the two occupied electric subbands. We focused specially on the fractional levels of the second subband, whose experimental values of the magnetic field B of their minima do not obey a periodicity law in 1/|B−Bc|, where Bc is the critical field at the filling factor ν=3/2, and we explain this fact entirely in the framework of the composite fermions theory. We use a simple theoretical model to give a possible explanation for the fact.
PACS: 71.30.+h – Metal-insulator transitions and other electronic transitions / 73.40.Qv – Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
© EPLA, 2011
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