Magnetic field induced charge redistribution in artificially disordered quantum Hall superlattices
Instituto de Física de São Carlos, Universidade de São Paulo - CEP 13560-970, São Carlos, SP, Brazil
2 Instituto de Física da Universidade de São Paulo - CP 66318, CEP 05315-970, São Paulo, SP, Brazil
3 Institute of Semiconductor Physics - Novosibirsk 630090, Russia
Accepted: 25 November 2011
The photoluminescence from individual quantum wells of artificially disordered weakly coupled multi-layers embedded in wide AlGaAs parabolic wells was investigated in a strong magnetic field. We show that the response of the individual wells is very different from the average response of the multi-layers studied by transport measurements and that photoluminescence represents a local probe of the quantum Hall state formed in three-dimensional electron system. The observed magnetic field induced variations of the in-layer electron density demonstrate the formation of a new phase in the quasi-three-dimensional electron system. The sudden change in the local electron density found at the Landau filling factor ν=1 by both the magneto-transport and the magneto-photoluminescence measurements was assigned to the quantum phase transition.
PACS: 73.43.Nq – Quantum phase transitions / 78.67.Pt – Multilayers; superlattices; photonic structures; metamaterials / 73.22.Gk – Broken symmetry phases
© EPLA, 2012