Lateral confinement and band mixing in ultrathin semiconductor quantum wells with steplike interfaces

Shtinkov, N.; Desjardins, P.; Masut, R. A.; Vlaev, S.

doi:10.1103/physrevb.70.155302

Cited by 10 publications

(19 citation statements)

References 42 publications

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“…The energy spectrum of quantum wire systems with a strong spin-orbit coupling has been studied both experimentally [239,890,891] and theoretically [191,240,241,890,[892][893][894][895][896]. Unlike the quantum wells discussed in Section 5.4, there is additional confinement in quantum wires, and the remaining free degree of freedom is along the wire growth direction.…”

Section: Spin Relaxation In Quantum Wiresmentioning

confidence: 97%

Spin dynamics in semiconductors

2010

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This article reviews the current status of spin dynamics in semiconductors which has achieved a lot of progress in the past years due to the fast growing field of semiconductor spintronics. The primary focus is the theoretical and experimental developments of spin relaxation and dephasing in both spin precession in time domain and spin diffusion and transport in spacial domain. A fully microscopic many-body investigation on spin dynamics based on the kinetic spin Bloch equation approach is reviewed comprehensively.Comment: a review article with 193 pages and 1103 references. To be published in Physics Reports

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Section: Spin Relaxation In Quantum Wiresmentioning

confidence: 97%

Spin dynamics in semiconductors

2010

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“…We have obtained a more precise estimate of these contributions to the e1-hh1 transition energy using the method described in Ref. 31. For an 11 ML thick and 20 nm wide QD, the contribution to the e1-hh1 transition is ϳ700 meV for the vertical confinement energy versus ϳ26 meV for the lateral confinement energy.…”

Section: Photoluminescence Characterizationmentioning

confidence: 99%

Intermixing during growth of InAs self-assembled quantum dots in InP: A photoluminescence and tight-binding investigation

et al. 2008

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Atomic intermixing during the growth of self-assembled InAs quantum dots ͑QDs͒ in InP͑001͒ by chemical beam epitaxy ͑CBE͒ can result in the formation of graded interfaces or even alloyed InAs 1−x P x QDs. Taking advantage of a series of samples in which photoluminescence ͑PL͒ spectra are characterized by the presence of a large number of distinct peaks corresponding to the emission from QD families having the same thicknesses ͑h QD ͒ in terms of an integer number of monolayers ͑MLs͒, we investigate intermixing by matching the experimentally observed transition energies to those calculated from tight-binding simulations. Two calculation frameworks are considered: ͑i͒ structures in which QDs are alloys with uniform P concentration ͓P͔ and ͑ii͒ nominally pure InAs QDs bordered by graded interfaces characterized by a diffusion length L D . Excellent agreement between theory and experiment is achieved with either framework. The analysis reveals that the two frameworks yield similar composition profiles as the composition at the center of the QD in the case of graded interfaces is modified to a point where it becomes essentially equal to that calculated for a QD of uniform composition. The calculations also indicate that in both frameworks, two substantially different solution sets are compatible with the experimental results. The first one is characterized by all QDs having the same P composition independent of their size, while the second solution shows a decreasing degree of intermixing with increasing h QD . To discriminate between the two solutions, we use them as input data in a Bloch-wave simulation of transmission electron microscopy ͑TEM͒ image contrast, providing a sequence of contrast versus h QD values. Only the scheme in which the amount of ͓P͔ is the same for all QD ensembles is compatible with the TEM observations. From the analysis of an extensive array of CBE-deposited QD samples, it is concluded that the observed PL transitions can be attributed to a 3 ML thick wetting layer and 4-14 ML thick QDs, with ͓P͔ ranging from 6% to 10% depending on the growth conditions. The determined values of ͓P͔ and L D suggest that surface As/ P exchange and strain-driven alloying are the most probable mechanisms for substantial P incorporation.

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“…The availability of powerful algorithms to compute the layer projections of Green's functions [8][9][10] has made this method extremely efficient in investigating a large class of 2D problems of great fundamental and applied importance. Among these one can mention the realistic simulation of scanning tunneling microscopy ͑STM͒ images, 11 quantum well interfaces, 12 superlattices, 13 and quasiperiodic structures. 14 A similar method has been developed for studying giant magnetoresistance in magnetic multilayers.…”

Section: Introductionmentioning

confidence: 99%

“…The 2D SGFM theory can be applied also in the special case of 1D systems with planar interfaces; this has been demonstrated in studies of deformed carbon nanotubes 16 and terraces at quantum well interfaces. 12,17 For 1D and 0D systems ͑wires and dots͒ with arbitrary interfaces, the problem is considerably more complicated and requires a complete rederivation of the matching equations taking into account the different topology of the system. Solutions have been found only for continuous systems with a simple symmetry such as a periodic array of cylindrical 1D wires 7 or muffin-tin spheres ͑0D͒.…”

Section: Introductionmentioning

confidence: 99%

“…To summarize, the SGFM theory has proven to be extremely useful in a wide variety of important computational problems: simulating STM images, 11 semiconductor heterostructures, [12][13][14]17 carbon nanotubes, 16 magnetic multilayers, 15 etc. At present, however, its practical applications are restricted to systems with planar interfaces, due to ͑i͒ the lack of a general SGFM method for 1D and 0D struc-tures with arbitrary interface shapes and ͑ii͒ the lack of efficient algorithms to calculate the interface projections of the domain Green's functions.…”

Section: Introductionmentioning

confidence: 99%

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Green’s function matching method for one- and zero-dimensional heterostructures

et al. 2005

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A method for the calculation of the Green's function of one-dimensional ͑wirelike͒ and zero-dimensional ͑boxlike͒ heterostructures is developed. The method is based on the formalism of surface Green's function matching ͑SGFM͒ for discrete media. The matching formulas are derived for structures consisting of an infinite "external" medium with an embedded array of wires ͑boxes͒, periodic in two ͑three͒ dimensions, for an arbitrary shape of the matching surface. Efficient algorithms to calculate the domain Green's functions are also proposed. Unlike the supercell methods widely used to compute the electronic structure of one-and zerodimensional systems that scale with the supercell size, the developed approach scales with the interface size, which makes it extremely efficient to study systems such as disordered alloys, clusters of defects, and nanoscale materials. We employ it to calculate the localized and extended electronic states of a periodic array of GaAs/ AlAs ͑001͒ nanowires using an sp 3 s * tight-binding Hamiltonian with spin-orbit coupling.

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Lateral confinement and band mixing in ultrathin semiconductor quantum wells with steplike interfaces

Cited by 10 publications

References 42 publications

Spin dynamics in semiconductors

Spin dynamics in semiconductors

Intermixing during growth of InAs self-assembled quantum dots in InP: A photoluminescence and tight-binding investigation

Green’s function matching method for one- and zero-dimensional heterostructures

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