Exciton Tunneling Revealed by Magnetically Tuned Interwell Coupling in Semiconductor Double Quantum Wells

Lawrence, I.; Haacke, S.; Mariette, H.; Rühle, W. W.; Ulmer-Tuffigo, H.; Cibert, J.; Feuillet, G.

doi:10.1103/physrevlett.73.2131

Cited by 65 publications

(51 citation statements)

References 21 publications

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“…In a field it is likely that excitonic effects will grow in importance because with increasing magnetic field the exciton binding energy is enhanced considerably, due to the Lorentz force induced reduction of the in-plane exciton radius [3]. Actually, Lawrence et al [2] observed tunneling of magnetoexcitons in CdTe based ADQW's, due to the increased exciton binding energy in a magnetic field, in addition to the enhanced binding energy in these kind of materials. In view of these considerations we postulate the observation of coupling of the Landau levels with different quantum number mediated by the Coulomb interaction of magnetoexcitons across the thin barrier.…”

Section: Discussionmentioning

confidence: 99%

“…For instance in GaAs based ADQW's it has been found that, although the carriers tunnel independently, the Coulomb interaction between electrons and holes strongly affects the tunneling behaviour [1]. Furthermore, Lawrence et al [2] have recently claimed that in CdTe based ADQW's the dominant transfer mechanism is associated with the tunneling of an exciton as a whole, which is favoured by the enhanced exciton binding energy in that material. Here we study the coupling between two GaAs QW's in high magnetic fields, directed perpendicular to the plane of the QW's, and therefore the tunneling occurs between quantized Landau levels.…”

Section: Introductionmentioning

confidence: 99%

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Carrier Tunneling in High Magnetic Fields

et al. 1995

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A magnetic field induced coupling is observed between the Landau levels with dicherent quantum number of two GaAs quantum wells separated by a thin (Ga,Al)As tunnel barrier using magneto-photoluminescence-excitation spectroscopy. This coupling cannot be due to a resonance between single particle energy levels, and therefore an explanatioii is proposed in terms of the Coulomb interaction of magneto-excitons across the thin barrier.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Carrier Tunneling in High Magnetic Fields

et al. 1995

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“…In wide-gap II-VI semiconductors, due to much larger exciton binding energies influence of excitonic effects on the tunneling process is more pronounced and can be studied. In particular, tunneling of excitons as whole quasiparticles can be observed besides the tunneling of separate electrons and holes [7,8,15], depending on the strength of coupling. A role of spatially indirect excitons formation as an intermediate relaxation states was revealed.…”

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confidence: 99%

Optical spin injection and tunneling in asymmetric coupled II–VI quantum wells

Nawrocki

Kłopotowski

Suffczyński

2004

Physica Status Solidi (b)

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We give an overview of recent results concerning exciton and carrier tunneling and relaxation in II-VI asymmetric double quantum wells structures with semimagnetic (diluted magnetic) wells or barriers. We undertake the issue of the spin relaxation and injection in the tunneling process and we discuss the dependence of the tunneling efficiency and spin injection on the energy detuning between the initial and final state of the process. The fast tunneling of excitons as whole entities was observed with efficiency strongly dependent on the barrier width, exciton detuning and the relation between detuning and optical phonon energy. In the energy transfer processes an important role of the charged excitons formation is observed. As a result of high sensitivity of energy levels in semimagnetic semiconductor to magnetic field, the thermodynamical redistribution of neutral and charged excitons dependence in magnetic field is observed and must be taken into account in the analysis.1 Introduction Asymmetric double quantum well (ADQW) structure forms an excellent laboratory for studying tunneling and related spin effects. It consists of two quantum wells (QWs) of different depth and/or width coupled through a barrier having width comparable to QW widths. In this system, usually the two lowest excitonic states are separated spatially but the overlap between the wave functions enables tunneling. ADQW structure based on the II-VI compounds is particularly useful in such investigations. It results from the possibility of technological realization of diverse designed structures due to a great number of available materials and their combinations. Simultaneously exciton binding energies in wide-gap II-VI semiconductors, few times larger compared to III-V materials, enable investigations of the influence of excitonic effects on the tunneling process. In addition, due to stronger coupling between excitons and longitudinal optical (LO) phonons in II-VI compounds than in III-V ones, phonon assisted tunneling plays a major role in the energy relaxation process and can be studied.The detuning between initial and final state of the tunneling process proves to be the parameter that controls the tunneling mechanism and, consequently, its efficiency. With the development of crystal growth techniques it became possible to accurately control the structure parameters and, as a consequence, the energy levels and wave function penetration through the barrier. However, to perform a detailed study of tunneling, it is preferable to tune continuously the energy levels and thus change tunneling conditions. A straightforward way of tuning the levels is using a diluted magnetic semiconductor (DMS) as a QW material. Due to s,p-d exchange interaction between manganese ions and band carriers, a giant Zeeman effect leads to 100 times larger band splitting than in a nonmagnetic material [33]. Therefore, a very efficient tuning of energy levels is possible with little modification of single particle or exci-

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“…1 Introduction Asymmetric double quantum wells (DQW) with magnetic barriers and non-magnetic wells have been used to study the quantum-mechanical tunnelling in the past [1][2][3][4][5][6]. A prominent system was CdTe/ (Cd,Mn)Te DQWs [6][7][8][9].…”

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Energy transfer in ZnSe/(Zn,Mn)Se double quantum wells

Jankowski

Heimbrodt

2010

Phys. Status Solidi (c)

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The complex interplay of energy transfer and tunnelling processes in asymmetric ZnSe/(Zn,Mn)Se double quantum well structures has been investigated. The optical properties at low temperatures and in an external magnetic fields up to 7 T show remarkable differences to earlier studies on CdTe/(Cd,Mn)Te double quantum wells. The pure quantum‐mechanical tunnelling‐process is only a minor contribution to the field dependence of the emission even in case of small barriers and strong quantum‐well coupling (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Exciton Tunneling Revealed by Magnetically Tuned Interwell Coupling in Semiconductor Double Quantum Wells

Cited by 65 publications

References 21 publications

Carrier Tunneling in High Magnetic Fields

Carrier Tunneling in High Magnetic Fields

Optical spin injection and tunneling in asymmetric coupled II–VI quantum wells

Energy transfer in ZnSe/(Zn,Mn)Se double quantum wells

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