Tight-binding model for semiconductor quantum dots with a wurtzite crystal structure: From one-particle properties to Coulomb correlations and optical spectra

We present an atomistic description of the electronic and optical properties of In0.25Ga0.75N/GaN quantum wells. Our analysis accounts for fluctuations of well width, local alloy composition, strain and built-in field fluctuations as well as Coulomb effects. We find a strong hole and much weaker electron wave function localization in InGaN random alloy quantum wells. The presented calculations show that while the electron states are mainly localized by well-width fluctuations, the holes states are already localized by random alloy fluctuations. These localization effects affect significantly the quantum well optical properties, leading to strong inhomogeneous broadening of the lowest interband transition energy. Our results are compared with experimental literature data.

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“…As the atomic orbitals are not explicitly known in an empirical TB approach, we approximate the Coulomb matrix elements by [37][38][39] …”

Section: Calculation Of Interaction Matrix Elementsmentioning

confidence: 99%

Atomistic analysis of the impact of alloy and well-width fluctuations on the electronic and optical properties of InGaN/GaN quantum wells

Schulz¹,

et al. 2015

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“…Note, that the FCI method is well established and was extensively applied to QD systems using a basis obtained by e.g., effective mass, 8 k Á p, 9 TB (Ref. 10), and emipirical pseudopotential 11 models. Before employing this many-body procedure, we discuss the calculation and optical properties of the localized single-particle QD states.…”

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confidence: 99%

Strong dipole coupling in nonpolar nitride quantum dots due to Coulomb effects

Schuh

Barthel

Marquardt

et al. 2012

Applied Physics Letters

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Optical properties of polar and nonpolar nitride quantum dots (QDs) are determined on the basis of a microscopic theory which combines a continuum elasticity approach to the polarization potential, a tight-binding model for the electronic energies and wavefunctions, and a many-body theory for the optical properties. For nonpolar nitride quantum dots, we find that optical absorption and emission spectra exhibit a weak ground-state oscillator strength in a single-particle calculation whereas the Coulomb configuration interaction strongly enhances the ground-state transitions. This finding sheds new light on existing discrepancies between previous theoretical and experimental results for these systems, as a weak ground state transition was predicted because of the spatial separation of the corresponding electron and hole state due to intrinsic fields whereas experimentally fast optical transitions have been observed.

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“…Further, we make use of the orthogonality of the atomic orbitals and assume that for sites which are apart from each other the exact structure of the localized orbitals is not important. 6 These assumptions yield approximate Coulomb matrix elements in the form…”

Section: F Coulomb and Dipole Matrix Elementsmentioning

confidence: 99%

“…7 and 8 for the purpose of this calculation we approximate the tight-binding orbitals with atomic Slater orbitals. Using similar assumptions as to the orthogonality of the orbitals we compute the dipole matrix elements ͑in this case for light polarized along x direction͒ as, 6,34…”

Section: F Coulomb and Dipole Matrix Elementsmentioning

confidence: 99%

“…Despite these difficulties a significant progress has been achieved using approximate methods. The multiexciton complexes in InAs SADs have been described using a combination of effective mass, [1][2][3] k · p, [1][2][3] atomistic tight-binding [4][5][6][7][8][9] and pseudopotential methods, 10,11 allowing computation of the single-particle states and the configuration-interaction approach accounting for the Coulomb interactions between carriers. We describe here several new developments in our understanding of multiexciton complexes.…”

Section: Introductionmentioning

confidence: 99%

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Multiexciton complexes in InAs self-assembled quantum dots

Korkusiński

Zieliński

Hawrylak

2009

Journal of Applied Physics

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We review our recent work on multiexciton complexes in InAs self-assembled quantum dots using a combination of effective mass, k⋅p, and atomistic sp3s∗d5 tight-binding approaches. The single-particle levels from effective mass, k⋅p, and atomistic tight-binding models are used as input into configuration-interaction calculation of multiexciton spectra. We describe the principles of the atomistic approach and apply all these computational tools to illustrate the concept of hidden symmetry as underlying principle in energy levels of multiexciton complexes, optical detection of electron spin polarization, tunneling of holes in quantum dot molecules, and tuning of multiexciton spectra with lateral electric fields for entangled photon pair generation.

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Tight-binding model for semiconductor quantum dots with a wurtzite crystal structure: From one-particle properties to Coulomb correlations and optical spectra

Cited by 110 publications

References 88 publications

Atomistic analysis of the impact of alloy and well-width fluctuations on the electronic and optical properties of InGaN/GaN quantum wells

Atomistic analysis of the impact of alloy and well-width fluctuations on the electronic and optical properties of InGaN/GaN quantum wells

Strong dipole coupling in nonpolar nitride quantum dots due to Coulomb effects

Multiexciton complexes in InAs self-assembled quantum dots

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