Role of Interface Imperfections on Intervalley Coupling in GaAs/AlAs Superlattices

Menchero, Jose; Koiller, Belita; Capaz, R. B.

doi:10.1103/physrevlett.83.2034

Cited by 14 publications

(17 citation statements)

References 13 publications

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“…37,38 The wave functions are written as ⌿ ϭ ͚ i c i ͉i͘ , where ͉i͘ are orthogonal normalized R i -centered orbitals of angular type ϭs,p x ,p y ,p z ,s* and spin , and c i are complex expansion coefficients. The s* orbital was first introduced by Vogl et al 39 to obtain a better description of the conduction bands.…”

Section: B Electronic Calculationsmentioning

confidence: 99%

“…Therefore by varying ⑀ r we may in principle determine all the electron and hole bound-state energies and wave functions. 47,37,38,51 Within our ETB formalism, strain effects can be formally removed from the electronic calculation by imposing n kl ϭ0 in Eq. ͑2͒ ͑removal of the strain and relaxation effects from bond lengths͒ and setting the direction cosines between atomic orbitals equal to the corresponding bulk values ͑re-moval of the strain and relaxation effects from bond angles͒.…”

Section: B Electronic Calculationsmentioning

confidence: 99%

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Tight-binding study of the influence of the strain on the electronic properties of InAs/GaAs quantum dots

et al. 2003

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We present an atomistic investigation of the influence of strain on the electronic properties of quantum dots ͑QD's͒ within the empirical sp 3 s* tight-binding ͑ETB͒ model with interactions up to second nearest neighbors and spin-orbit coupling. Results for the model system of capped pyramid-shaped InAs QD's in GaAs, with supercells containing ϳ10 5 atoms are presented and compared with previous empirical pseudopotential results. The good agreement shows that ETB is a reliable alternative for an atomistic treatment. The strain is incorporated through the atomistic valence-force field model. The ETB treatment allows for the effects of bond length and bond angle deviations from the ideal InAs and GaAs zinc-blende structure to be selectively removed from the electronic-structure calculation, giving quantitative information on the importance of strain effects on the bound-state energies and on the physical origin of the spatial elongation of the wave functions. Effects of dot-dot coupling have also been examined to determine the relative weight of both strain field and wavefunction overlap.

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Section: B Electronic Calculationsmentioning

confidence: 99%

Section: B Electronic Calculationsmentioning

confidence: 99%

Tight-binding study of the influence of the strain on the electronic properties of InAs/GaAs quantum dots

et al. 2003

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“…These treatments naturally involve an additional parameter, namely the G-X coupling, which emerges from the broken 3D translational symmetry of the zinc-blende heterostructure constituents. This parameter is strongly dependent on the geometry of the system [7]. Moreover, the inclusion of an external electric field also affects its value.…”

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Electric-Field Effects on the Band-Edge States of GaAs/AlAs Coupled Quantum Wells

Ribeiro

Capaz

Koiller

2002

phys. stat. sol. (b)

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PACS: 73.21.FgOptical experiments on electric field tunable AlAs/GaAs coupled quantum wells demonstrate that the optical nature of these structures can be directly controlled by an applied electric field. In this work we are concerned with calculation and analysis of the first electron and hole states in these structures. We take into account the effects of the heterostrucuture geometry and of the external uniform electric field applied perpendicularly to the layers, which may lead to an anticrossing of low-lying electron levels in the system. Calculations are performed within the tight-binding supercell formalism with interactions between atomic orbitals up to second nearest neighbors. Our results show that for GaAs layers less than %30 A wide, the application of electric fields turns the heterostructures from type II to type I behavior. Our estimated value of the electric field intensity needed to realize this transition is in good agreement with the experimental results for comparable heterostructure geometry.

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“…

The quantum mechanical mixing between bulk G and X z states due to superlattice potential in AlAs m =GaAs n superlattices (SLs) is of great importance for the electronic and optical properties of the SL [1,2,3]. The G±X z coupling has been calculated for a single segregated interface [4] and for the case of random exchange of atoms between the adjacent atomic planes at the interface [5].In this Note, we investigate for the first time the effect of interdiffusion on the G±X z coupling in (001) AlAs m =GaAs n SLs. Until now however there has been almost no theoretical investigations of this important question.

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confidence: 99%

“…The electronic structure is obtained using the surface Green function matching formalism developed in [10] for SLs, and an algorithm for calculating the Green function of a non-homogeneous slab [9]. Other theoretical calculations [4,5] give similar values for V GX , however we should note that in [5] the tight-binding parameters at the interface are modified to fit the experimental value of V GX , while we have used the bulk parameters without any modifications beyond the virtual crystal approximation. In agreement with the latter we have obtained zero coupling for odd values of m, which remains zero also for diffused interfaces.…”

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?-X Coupling in Diffused AlAs/GaAs Superlattices

Shtinkov¹,

Vlaev²

2000

phys. stat. sol. (b)

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Role of Interface Imperfections on Intervalley Coupling in GaAs/AlAs Superlattices

Cited by 14 publications

References 13 publications

Tight-binding study of the influence of the strain on the electronic properties of InAs/GaAs quantum dots

Tight-binding study of the influence of the strain on the electronic properties of InAs/GaAs quantum dots

Electric-Field Effects on the Band-Edge States of GaAs/AlAs Coupled Quantum Wells

?-X Coupling in Diffused AlAs/GaAs Superlattices

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