Theory of exciton fine structure in semiconductor quantum dots: Quantum dot anisotropy and lateral electric field

Kadantsev, Eugene S.; Hawrylak, Paweł

doi:10.1103/physrevb.81.045311

Cited by 60 publications

(94 citation statements)

References 28 publications

(84 reference statements)

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“…The dependence of the FSS on an in-plane electric field has been experimentally studied and it was confirmed that the FSS can be removed [12,13] but a complete theoretical understanding is still missing. Earlier work using a harmonic dot confinement potential find qualitatively different results [10]. Here we use a more realistic confinement potential and compare the obtained FSS to the one from harmonic confinement and to experimental results.…”

mentioning

confidence: 85%

“…A similar expression was presented by Kadantsev and Hawrylak [10] as well as by Tong and Wu [11]. If we let t , t represent valence band electrons we need to reverse the order and apply the time-reversal operator when going over from the electron-electron picture to the electron-hole picture.…”

mentioning

confidence: 99%

“…These include intrinsic effects caused by the underlying crystal orientation [4][5][6][7], piezoelectric effects [8] and the QD geometry [9][10][11]. There is a fundamental physical difference between the intrinsic splitting and geometry dependent splitting.…”

mentioning

confidence: 99%

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Electric control of the exciton fine structure in nonparabolic quantum dots

Welander¹,

Burkard²

2012

Phys. Rev. B

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We show that the non-parabolic confinement potential is responsible for the non-monotonic behavior and sign change of the exciton fine-structure splitting (FSS) in optically active self-assembled quantum dots. This insight is important for the theoretical understanding and practical control by electric fields of the quantum state of the emitted light from a biexciton cascade recombination process. We find that a hard-wall (box) confinement potential leads to a FSS that is in better agreement with experimentally measured FSS than a harmonic potential. We then show that a finite applied electric field can be used to remove the FSS entirely, thus allowing for the creation of maximally entangled photons, being vital to the growing field of quantum communication and quantum key distribution.

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confidence: 85%

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confidence: 99%

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Electric control of the exciton fine structure in nonparabolic quantum dots

Welander¹,

Burkard²

2012

Phys. Rev. B

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“…In another words the origin of the LRE was ascribed to asymmetry of the confinement potential. It was also found that the lower energy exciton component is polarized along the elongation axis of the confinement potential [56]- [58]. However the nature of the LRE part (i.e.…”

Section: Exchange Interaction In Zero Dimensional Semiconductor Strucmentioning

confidence: 99%

“…The second group is based on the effective mass approximation within the kp method framework [49], [55]- [58]. Thus the problem is reduced in this approach to finding the envelope functions as function of position.…”

Section: Exchange Interaction In Zero Dimensional Semiconductor Strucmentioning

confidence: 99%

Micro-photoluminescence and micro-Raman spectroscopy of novel semiconductor nanostructures

Filippov¹

2016

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Abstract.Low-dimensional semiconductor structures, such as one-dimensional nanowires (NWs) and zero-dimensional quantum dots (QDs), are materials with novel fundamental physical properties and a great potential for a wide range of nanoscale device applications. Here, especially promising are direct bandgap II-VI and III-V compounds and related alloys with a broad selection of compositions and band structures. For examples, NWs based on dilute nitride alloys, i.e. GaNAs and GaNP, provide both an optical active medium and well-shaped cavity and, therefore, can be used in a variety of advanced optoelectronic devices including intermediate band solar cells and efficient light-emitters. Self-assembled InAs QDs formed in the GaAs matrix are proposed as building blocks for entangled photon sources for quantum cryptography and quantum information processing as well as for spin light emitting devices. ZnO NWs can be utilized in a variety of applications including efficient UV lasers and gas sensors. In order to fully explore advantages of nanostructured materials, their electronic properties and lattice structure need to be comprehensively characterized and fully understood, which is not yet achieved in the case of aforementioned material systems. The research work presented this thesis addresses a selection of open issues via comprehensive optical characterization of individual nanostructures using micro-Raman (-Raman) and microphotoluminescence (-PL) spectroscopies.In paper 1 we study polarization properties of individual GaNP and GaP/GaNP core/shell NWs using polarization resolved µ-PL spectroscopy. Near band-edge emission in these structures is found to be strongly polarized (up to 60% at 150K) in the orthogonal direction to the NW axis, in spite of their zinc blende (ZB) structure. This polarization response, which is unusual for ZB NWs, is attributed to the local strain in the vicinity of the N-related centers participating in the radiative recombination and to their preferential alignment along the growth direction, presumably caused by the presence of planar defects. Our findings therefore show that defect engineering via alloying with nitrogen provides an additional degree of freedom to control the polarization anisotropy of III-V nanowires, advantageous for their applications as a nanoscale source of polarized light.Structural and optical properties of novel coaxial GaAs/Ga(N)As NWs grown on Si II substrates, were evaluated in papers 2-4. In paper 2 we show by using -Raman spectroscopy that, though nitrogen incorporation shortens a phonon correlation length, the GaNAs shell with [N]<0.6% has a low degree of alloy disorder and weak residual strain.Additionally, Raman scattering by the GaAs-like and GaN-like phonons is found to be enhanced when the excitation energy approaches the E + transition energy. This effect was attributed the involvement of intermediate states that were created by N-related clusters in proximity to the E + subband. Recombination processes in these structures were studied in paper 3 by ...

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Unpinning of heavy hole spin in magnetic quantum dots

Dinu

Moldoveanu

Dragomir

et al. 2016

Physica Status Solidi (b)

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Using the k·p theory and configuration interaction method, we analyze the effect of heavy hole–light hole (HH–LH) mixing in CdTe quantum dots (QDs) with a single manganese (Mn) ion. We find that the hole‐Mn exchange switches the coupling between two excitons whose Luttinger spinors have both HH and LH components. If the magnetic dopant is off‐centered and the QD is subjected to a single π pulse the system periodically bounces between bright and dark mostly HH excitons with opposite HH spins. A pump‐and‐probe setup allows to estimate the efficiency of this HH spin unpinning from the biexciton response. The biexciton absorption spectrum is also discussed.

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Theory of exciton fine structure in semiconductor quantum dots: Quantum dot anisotropy and lateral electric field

Cited by 60 publications

References 28 publications

Electric control of the exciton fine structure in nonparabolic quantum dots

Electric control of the exciton fine structure in nonparabolic quantum dots

Micro-photoluminescence and micro-Raman spectroscopy of novel semiconductor nanostructures

Unpinning of heavy hole spin in magnetic quantum dots

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