Confinement-induced depletion of the enhanced<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>g</mml:mi></mml:math>-factor in quantum wires

Struck, Alexander; Mohammadi, Siawoosh; Kettemann, Stefan; Krämer, B.

doi:10.1103/physrevb.72.245317

Cited by 8 publications

(8 citation statements)

References 17 publications

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“…9 The effect of the many-body interactions on the spin splitting in quantum wires in the IQH regime has been a subject of numerous studies. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] These studies have focused on various aspects of 2DEG in confined geometries including the structure of compressible/incompressible strips, suppression or enhancement of the g factor, subband spin splitting, spatial spin separation, and others. We, however, have not been able to find in the literature any systematic quantitative treatment of the magnetoconductance of the structures at hand.…”

Section: Introductionmentioning

confidence: 99%

Magnetoconductance of interacting electrons in quantum wires: Spin density functional theory study

Ihnatsenka

Zozoulenko

2008

Phys. Rev. B

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We present a systematic quantitative description of the magnetoconductance of split-gate quantum wires focusing on formation and evolution of the odd ͑spin-resolved͒ conductance plateaus. We start from the case of spinless electrons where the calculated magnetoconductance in the Hartree approximation shows the plateaus quantized in units of 2e 2 / h separated by transition regions, whose width grows as the magnetic field is increased. We show that the transition regions are related to the formation of the compressible strips in the middle of the wire occupied by electrons belonging to the highest ͑spin-degenerate͒ subband. Accounting for the exchange and correlation interactions within the spin density functional theory ͑DFT͒ leads to the lifting of the spin degeneracy and formation of the spin-resolved plateaus at odd values of e 2 / h. The most striking feature of the magnetoconductance is that the width of the odd conductance steps in the spin DFT calculations is equal to the width of the transition intervals between the conductance steps in the Hartree calculations. A detailed analysis of the evolution of the Hartree and the spin DFT subband structure provides an explanation of this finding. Our calculations also reveal the effect of the collapse of the odd conductance plateaus for lower fields. We attribute this effect to the reduced screening efficiency in the confined ͑wire͒ geometry when the width of the compressible strip in the center becomes much smaller than the extent of the wave function. A detailed comparison to the experimental data demonstrates that the spin DFT calculations reproduce not only qualitatively but also quantitatively all the features observed in the experiment. This includes the dependence of the width of the odd and even plateaus on the magnetic field as well as the estimation of the subband index corresponding to the last resolved odd plateau in the magnetoconductance.

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Section: Introductionmentioning

confidence: 99%

Magnetoconductance of interacting electrons in quantum wires: Spin density functional theory study

Ihnatsenka

Zozoulenko

2008

Phys. Rev. B

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“…This might be an indication for an enhanced Zeeman splitting in one-dimensional systems. 14,[23][24][25] In conclusion, the Zeeman energy splitting between onedimensional subbands in a Ga x In 1−x As/ InP split-gate point contact was determined by measuring the differential conductance as a function of V sd . Owing to the large g factor of approximately 4, Zeeman splitting between the subbands was resolved at fields as low as 1 T. At 8 T a Zeeman splitting as large as 2 meV has been observed.…”

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confidence: 99%

Zeeman splitting in ballistic GaInAs∕InP split-gate quantum point contacts

Schäpers

Guzenko

Hardtdegen

2007

Applied Physics Letters

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In 1−x As/ InP split-gate point contacts was investigated. The measurements were performed in a magnetic field perpendicular to the plane of the two-dimensional electron gas. The Zeeman energy splitting between the one-dimensional subbands was determined by measuring the differential conductance as a function of the dc source-drain voltage across the point contact. The g factor of approximately 4.0 extracted from measurements at various magnetic fields agrees well to the value obtained by other methods for this type of heterostructure.

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“…Preliminary results for larger systems show that the fluctuations seem to remain present. A systematic study of the size dependence will be reported elsewhere [20].…”

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Electron Correlations and Single-Particle Physics in the Integer Quantum Hall Effect

Struck

Krämer²

2006

Phys. Rev. Lett.

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The compressibility of a two-dimensional electron system with spin in a spatially correlated random potential and a quantizing magnetic field is investigated. Electron-electron interaction is treated with the Hartree-Fock method. Numerical results for the influences of interaction and disorder on the compressibility as a function of the particle density and the strength of the magnetic field are presented. Localization-delocalization transitions associated with highly compressible region in the energy spectrum are found at half-integer filling factors. Coulomb blockade effects are found near integer fillings in the regions of low compressibility. Results are compared with recent experiments.The integer quantization of the Hall conductance of a two-dimensional electron system (2DEG) in a strong magnetic field[1] can be understood in terms of quantum phase transitions near the centres of the Landau bands associated with disorder-induced localizationdelocalization transitions of single-electron states in a one parameter scaling model. Neglecting interaction, the localization length has been found diverging, ξ ∝ |E − E C | −ν , with the critical energy E c . The universal value of the critical exponent,ν = 2.34 ± 0.04 [2,3], is widely accepted. Peaks in the magneto-conductance are associated with E c . The localized states in the band tails are associated with zero conductance at zero temperature [4].Despite consistency with several transport experiments [5], the validity of the one-parameter scaling model has been controversely discussed, in particular the impact of interaction on the frequency-dependent scaling of the conductivity and the tunneling density of states [6,7,8].In recent experiments, mesoscopic conductance fluctuations found in silicon metal-oxide-semiconductor fieldeffect transistors in dc-transport show regular patterns which have been interpreted as charging effects [9]. Patterns associated with Coulomb blockade in localized states have also been found in measurements of the shift dµ/dn of the chemical potential µ with a scanning singleelectron transistor probe when changing the particle density n [10]. The latter results have been interpreted in a model in which the quantum Hall transition appears as a result of the strong and complete screening of the disorder potential near half-integer filling factors. The absence of screening in the incompressible regions of the energy spectrum leads to localized states that account for the observed charging effects. In this model, the phase transition has been interpreted as a percolation transition between incompressible and compressible regions at certain concentrations of localized charge islands.We report results of an extensive unrestricted HartreeFock (HF) study of the 2DEG with spin in the presence of long-range correlated disorder and a perpendicular magnetic field that can contribute towards more detailed understanding of the experiments. We have studied the change dµ/dn of the chemical potential µ with the particle density n = N/L 2 of N particles i...

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Confinement-induced depletion of the enhancedg-factor in quantum wires

Cited by 8 publications

References 17 publications

Magnetoconductance of interacting electrons in quantum wires: Spin density functional theory study

Magnetoconductance of interacting electrons in quantum wires: Spin density functional theory study

Zeeman splitting in ballistic GaInAs∕InP split-gate quantum point contacts

Electron Correlations and Single-Particle Physics in the Integer Quantum Hall Effect

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