Magneto-optical properties of charged excitons in quantum dots

Schulhauser, C.; Haft, D.; Warburton, Richard J.; Karraï, K.; Govorov, Alexander O.; Kalameitsev, A. V.; Chaplik, A. V.; Schoenfeld, Winston V.; García, J. M.; Petroff, P. M.

doi:10.1103/physrevb.66.193303

Cited by 68 publications

(60 citation statements)

References 22 publications

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“…Using magneto-photoluminescence spectroscopy, fine-structure splitting [29], Zeeman splitting [30,31] and diamagnetic shift [32,33] have been investigated for different charge states in single quantum dots. Recently, coupling between triply negatively charged states and the wetting layer has also been shown using magneto-photoluminescence [34,35].…”

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confidence: 99%

Charge state control in single InAs/GaAs quantum dots by external electric and magnetic fields

Tang

Cao

Gao

et al. 2014

Applied Physics Letters

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We report a photoluminescence (PL) spectroscopy study of charge state control in single selfassembled InAs/GaAs quantum dots by applying electric and/or magnetic fields at 4.2 K. Neutral and charged exciton complexes were observed under applied bias voltages from -0.5 V to 0.5 V by controlling the carrier tunneling. The highly negatively charged exciton emission becomes stronger with increasing pumping power, arising from the fact that electrons have a smaller effective mass than holes and are more easily captured by the quantum dots. The integrated PL intensity of negatively charged excitons is affected significantly by a magnetic field applied along the sample growth axis. This observation is explained by a reduction in the electron drift velocity caused by an applied magnetic field, which increases the probability of non-resonantly excited electrons being trapped by localized potentials at the wetting layer interface, and results in fewer electrons distributed in the quantum dots. The hole drift velocity is also affected by the magnetic field, but it is much weaker.

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confidence: 99%

Charge state control in single InAs/GaAs quantum dots by external electric and magnetic fields

Tang

Cao

Gao

et al. 2014

Applied Physics Letters

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“…2b, as for X 0 and X 1− [11]. The line width for both triplet and singlet X 2− emission increases surprisingly rapidly with temperature at a rate much larger than for X 0 and X 1− .…”

Section: The Doubly Charged Exciton X 2−mentioning

confidence: 78%

“…In a magnetic field the behaviour of the X 0 and X 1− is typical of localized excitons [11]. There is a diamagnetic shift, quadratic in magnetic field B, arising from the enhancement of the exciton confinement, and a splitting, linear in B, arising from the spin Zeeman effect, see The PL is represented with a grey scale, and the magnetic field is applied perpendicular to the quantum dot plane.…”

Section: The Neutral Exciton X 0 and The Trion X 1−mentioning

confidence: 99%

Spin-Dependent Coupling of Charged Quantum Dot Excitons with Continuum States

et al. 2004

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Magnetic field and temperature dependent photoluminescence studies on neutral and charged excitons in individual InAs quantum dots allow us to uncover different mechanisms by which the discrete quantum dot states are coupled to delocalized continuum states in a quantum well (the wetting layer). The behaviour of the neutral and singly charged excitons can be explained taking only discrete quantum dot states into account. For doubly and triply charged excitons we have to consider spin dependent coherent and incoherent interactions between discrete quantum dot states and delocalized wetting layer states.

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“…A magnetic field applied in the growth direction splits the X 1− transition into two lines separated by the Zeeman energy E Z = g * µ B B, where g * is the exciton g-factor and µ B the Bohr magneton. In our sample, a typical value of g * is −2 leading to a characteristic Zeeman splitting of ∼ 120 µeV/ T 2 [27]. Fig.…”

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confidence: 72%

Voltage-Controlled Electron-Hole Interaction in a Single Quantum Dot

et al. 2005

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The ground state of neutral and negatively charged excitons confined to a single self-assembled InGaAs quantum dot is probed in a direct absorption experiment by high resolution laser spectroscopy. We show how the anisotropic electron-hole exchange interaction depends on the exciton charge and demonstrate how the interaction can be switched on and off with a small dc voltage. Furthermore, we report polarization sensitive analysis of the excitonic interband transition in a single quantum dot as a function of charge with and without magnetic field.Spin control and manipulation in mesoscopic semiconductor systems have attracted extensive attention within the last few years. The activity in this field is driven by the idea of using spin states for quantum information processing and quantum communication. In particular, semiconductor quantum dots (QDs) have been considered for realization of spin quantum bits [1, 2] as they offer the potential advantage of scalability and tunability. For spin qubit processing in QDs, an optical scheme has been envisioned [3]. Other proposals involve a combination of spin and charge excitation [4] or an all-optical implementation of quantum information processing [5] in QDs. All proposals have a common crucial requirement, namely resonant and spin selective excitation.Significant progress has been made with naturally formed QDs [6] based on resonant control of excitonic states [7,8], leading to the recent demonstration of an optical CROT gate [9]. Self-assembled QDs have the advantage of longer excitonic coherence time due to stronger confinement. They have been proved to serve as a source of non-classical light for secure quantum communication [10,11,12,13]. An implementation of self-assembled QDs as a spin sensitive post processing read-out tool can be envisioned. Electric dipole transitions are spin sensitive, such that the spin information of the optically active state is imprinted onto the photon polarization. High efficiency single photon devices [14] could provide high yield for spin qubit detection.Recently, we have reported resonant exciton creation into the ground state [15,16] and the first excited state [17] of a single self-assembled QD. In the work presented here, we address the topic of polarization selective resonant creation of excitonic states in a single self-assembled InGaAs QD by high resolution laser spectroscopy. We report results on the spin mediated anisotropic electron-hole exchange and on the polarization dependence of the excitonic states as function of charge, electric and magnetic field.The InGaAs QDs investigated in the experiments were grown by molecular beam epitaxy in the self-assembly Stranski-Krastanow mode and are embedded in a field effect heterostructure [18]. Highly n-doped GaAs acts as back electrode followed by a tunnel barrier of 25nm GaAs and the InGaAs QDs. An annealing step was introduced in order to shift the photoluminescence (PL) emission energy to around 1.3 eV [19]. The QDs are sequentially capped with 30 nm GaAs and a 120 nm AlAs/GaA...

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Magneto-optical properties of charged excitons in quantum dots

Cited by 68 publications

References 22 publications

Charge state control in single InAs/GaAs quantum dots by external electric and magnetic fields

Charge state control in single InAs/GaAs quantum dots by external electric and magnetic fields

Spin-Dependent Coupling of Charged Quantum Dot Excitons with Continuum States

Voltage-Controlled Electron-Hole Interaction in a Single Quantum Dot

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