Frequency-dependent C(V) spectroscopy of the hole system in InAs quantum dots

Reuter, D.; Schafmeister, P.; Kailuweit, P.; Wieck, A. D.

doi:10.1016/j.physe.2003.11.055

Cited by 17 publications

(20 citation statements)

References 14 publications

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“…4 Only very recent C-V spectroscopy experiments have succeeded in resolving a number of energy levels corresponding to holes confined in In͑Ga͒As selfassembled QDs. [5][6][7][8] Of particular interest are the results reported by Reuter et al,7,8 which studied the energy dispersion of hole charging peaks in QDs with a magnetic field B applied along the growth direction. It was found that for QDs charged on average with one or two holes, the slope of the peaks dispersion was approximately zero.…”

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confidence: 99%

Magnetic-field dependence of hole levels in self-assembledInGaAsquantum dots

Climente¹,

Planelles²,

Pí³

et al. 2005

Phys. Rev. B

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Phys. Rev. Lett. 94, 026808 ͑2005͔͒ are interpreted by employing a multiband k · p Hamiltonian, which considers the interaction between heavy hole and light hole subbands explicitly. No need of invoking an incomplete energy shell filling is required within this model. The crucial role we ascribe to the heavy hole-light hole interaction is further supported by one-band local-spin-density functional calculations, which show that Coulomb interactions do not induce any incomplete hole shell filling and therefore cannot account for the experimental magnetic field dispersion. DOI: 10.1103/PhysRevB.72.233305 PACS number͑s͒: 73.21.La, 73.22.Ϫf, 73.23.Hk Knowledge of the electronic structure of semiconductor quantum dots ͑QDs͒ 1 is essential to understand and predict their physical properties. The energy structure of conduction band electrons confined in QDs has been thoroughly investigated using capacitance-voltage ͑C-V͒ 2 and far-infrared absorption spectroscopy. 3 However, direct and clear access to the energy structure of valence band holes has long been hindered by the high density of states arising from their larger effective mass. 4 Only very recent C-V spectroscopy experiments have succeeded in resolving a number of energy levels corresponding to holes confined in In͑Ga͒As selfassembled QDs. [5][6][7][8] Of particular interest are the results reported by Reuter et al.,7,8 which studied the energy dispersion of hole charging peaks in QDs with a magnetic field B applied along the growth direction. It was found that for QDs charged on average with one or two holes, the slope of the peaks dispersion was approximately zero. When the QDs were charged with three to six holes, the peaks shifted toward lower and higher energy in alternating fashion, the slope of the fifth and sixth peaks being about twice as strong as that of the third and fourth ones. By using a one-band effective mass Hamiltonian, such results were interpreted as a nonsequential shell filling, leading to highly spin-polarized ground states. 7 It was speculated that this phenomenon, which has no analogy in conduction band electrons, might be due to the Coulomb exchange interactions exceeding the rather small kinetic energy of holes.In this paper, we provide theoretical support for these experiments. First, we study the effect of Coulomb correlations on the electronic configuration of the hole ground state in self-assembled In͑Ga͒As QDs. To this end, we use a oneband local-spin-density functional ͑LSDF͒ model. We find that, even for a rather large QD and pure heavy hole effective mass, a sequential filling of the energy levels is predicted. It then follows that an explanation for the experimental magnetic field-induced dispersion of the charging peaks is unattainable within the one-band picture. Next, we study the role of heavy hole-light hole ͑HH-LH͒ coupling, using a fourband Luttinger-Kohn Hamiltonian. Our results show that HH-LH interaction, together with the spin Zeeman splitting, yield a plausible interpretation of the experimental data even at ...

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confidence: 99%

Magnetic-field dependence of hole levels in self-assembledInGaAsquantum dots

Climente¹,

Planelles²,

Pí³

et al. 2005

Phys. Rev. B

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“…When considering tunneling into a twofold degenerate s-state, i.e. g + = 2 and g − = 1, we obtain a relative peak height of 16/25 for a measurement frequency equal to the tunneling rate Γ e causing a correction to the value 1/2 obtained when neglecting degeneracies [22].…”

Section: B Simple Examplementioning

confidence: 80%

Illumination-induced nonequilibrium charge states in self-assembled quantum dots

et al. 2018

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We report on capacitance-voltage spectroscopy of self-assembled InAs quantum dots under constant illumination. Besides the electronic and excitonic charging peaks in the spectrum reported earlier, we find additional resonances associated with nonequilibrium state tunneling unseen in C(V) measurements before. We derive a master-equation based model to assign the corresponding quantum state tunneling to the observed peaks. C(V) spectroscopy in a magnetic field is used to verify the model-assigned nonequilibrium peaks. The model is able to quantitatively address various experimental findings in C(V) spectroscopy of quantum dots such as the frequency and illumination dependent peak height, a thermal shift of the tunneling resonances and the occurrence of the additional nonequilibrium peaks.

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“…Six clearly resolved charging peaks and an additional broad one probably composed from two peaks are observed. By converting the gate voltage scale to an energy scale, employing a method described in [5], one can determine the energetic position for the first six charging peaks. In Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Whereas the conduction band states have been intensively investigated, e.g., by capacitance-voltage (C-V) spectroscopy [2,3], only very recently the hole charging spectra could be accessed with high resolution [4][5][6]. Compared to electrons, the charging peaks for holes show a significantly different dispersion behavior in perpendicular (parallel to the growth direction) magnetic field and, within a simple effective mass model, a charging sequence with an incomplete shell filling was proposed to explain the observed dispersion behavior [6].…”

Section: Introductionmentioning

confidence: 99%

Hole and electron wave functions in self‐assembled InAs quantum dots: a comparison

Reuter

Kailuweit

Roescu

et al. 2006

Physica Status Solidi (b)

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We have investigated the conduction and the valence band states of self-assembled InAs quantum dots embedded in n-and p-type Schottky diodes, respectively, by magneto-capacitance voltage spectroscopy. The dispersion behaviour of the individual charging peaks in a perpendicular magnetic field shows qualitative differences between the two carrier types. By applying an in-plane magnetic field, the momentum space wave function corresponding to the individual charging peaks could be mapped. For electrons, the s-like wave function for the ground state is slightly asymmetric with the low energy direction along [0 11] in real space. Also the s-like wave function for the hole ground state is asymmetric but here the low energy direction is along [011], i.e. orthogonal to that for electrons. This hints to an asymmetry in the confinement potential that is caused by piezoelectric effects.

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Frequency-dependent C(V) spectroscopy of the hole system in InAs quantum dots

Cited by 17 publications

References 14 publications

Magnetic-field dependence of hole levels in self-assembledInGaAsquantum dots

Magnetic-field dependence of hole levels in self-assembledInGaAsquantum dots

Illumination-induced nonequilibrium charge states in self-assembled quantum dots

Hole and electron wave functions in self‐assembled InAs quantum dots: a comparison

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