Open Access Nano Express

Circular polarization in a non-magnetic resonant tunneling device

Lara F dos Santos1, Yara Galvão Gobato1*, Márcio D Teodoro1, Victor Lopez-Richard1, Gilmar E Marques1, Maria JSP Brasil2, Milan Orlita36, Jan Kunc36, Duncan K Maude3, Mohamed Henini4 and Robert J Airey5

Author Affiliations

1 Physics Department, Federal University of São Carlos, São Carlos, Brazil

2 Physics Institute, UNICAMP, Campinas, Brazil

3 Grenoble High Magnet Field Laboratory, Grenoble, France

4 School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, Nottingham, NG7 2RD, UK

5 EPSRC National Centre for III-V Technologies, The University of Sheffield, Sheffield, UK

6 Institute of Physics, Charles University, Ke Karlovu 5, 121 16 Praha 2, Czech Republic

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Nanoscale Research Letters 2011, 6:101  doi:10.1186/1556-276X-6-101

Published: 25 January 2011

Abstract

We have investigated the polarization-resolved photoluminescence (PL) in an asymmetric n-type GaAs/AlAs/GaAlAs resonant tunneling diode under magnetic field parallel to the tunnel current. The quantum well (QW) PL presents strong circular polarization (values up to -70% at 19 T). The optical emission from GaAs contact layers shows evidence of highly spin-polarized two-dimensional electron and hole gases which affects the spin polarization of carriers in the QW. However, the circular polarization degree in the QW also depends on various other parameters, including the g-factors of the different layers, the density of carriers along the structure, and the Zeeman and Rashba effects.