Hysteresis and spin phase transitions in quantum wires in the integer quantum Hall regime

Ihnatsenka, S.; Zozoulenko, Igor

doi:10.1103/physrevb.75.035318

Cited by 20 publications

(41 citation statements)

References 37 publications

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“…The model is implemented within the Green's function formalism that is well suited to the description of structures of arbitrary geometries. 1,2,[14][15][16]20,24 It was previously tested (without the Fock term) on different low-dimensional structures and the results obtained were in good agreement with experimental data and other theoretical models. 2,14,15 An attempt to account for exchange interaction was previously done using DFT in the local density approximation.…”

Section: Introductionsupporting

confidence: 53%

First-principles study of electron transport in few-electron open quantum dots by the Hartree–Fock approach

Ihnatsenka

2012

Physica E: Low-dimensional Systems and Nanostructures

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Electron transport properties of few-electron open quantum dots within the spin-restricted Hartree-Fock approximation are studied. The self-consistent numerical calculations were performed for a whole device, including the semi-infinite leads, without employing any phenomenological or adjustable parameters. Inclusion of the non-local Fock potential brings qualitatively new physics in comparison to the Hartree approach: electron screening decreases, resonant energy levels become less pinned to the Fermi energy and clearly correlate with conductance peaks. When coupling between the dot and leads decreases the number of electrons inside the dot becomes quantized and the model predicts the Coulomb blockade of electron transport. This is confirmed by comparison with the master equation approach for an equivalent quantum dot.

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Section: Introductionsupporting

confidence: 53%

First-principles study of electron transport in few-electron open quantum dots by the Hartree–Fock approach

Ihnatsenka

2012

Physica E: Low-dimensional Systems and Nanostructures

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“…Each time an energy level crosses E F electrons start populating the GN and contribute to the electrical conductance. Note that the bottoms of the subbands in the GN do not show any pinning to the Fermi level such as that observed in conventional quantum wires 27 and open quantum dots 22 . As can be seen in Fig.…”

Section: Modelmentioning

confidence: 74%

“…In order to include electron-electron interactions over the whole system, we partition the system into three parts, the internal computational region and two semi-infinite leads. 21,22 The internal region incorporates not only the constriction but also segments of uniform ribbon on both sides of it, including part of the leads. The semi-infinite leads themselves begin far enough from the constriction to ensure that the total self-consistent potential and the electron density do not change appreciably along the leads, i.e., the electron density and the potential in the leads are not affected by the internal region.…”

Section: Modelmentioning

confidence: 99%

Effect of electron-electron interactions on the electronic structure and conductance of graphene nanoconstrictions

Ihnatsenka

Kirczenow

2012

Phys. Rev. B

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We present self-consistent calculations of electron transport in graphene nanoconstrictions within the Hartree approximation. We consider suspended armchair ribbons with V-shaped constrictions having perfect armchair or zigzag edges as well as mesoscopically smooth but atomically stepped constrictions with cosine profiles. Our calculations are based on a tight-binding model of the graphene and account for electron-electron interactions in both the constriction and the semi-infinite leads explicitly. We find that electron interactions result in (i) Electrons accumulating along edges of the uniform ribbon and along zigzag and cosine constriction edges but not along armchair constriction edges. (ii) The first subband showing almost perfect transmittance due to localization at the uniform graphene boundary except at low energies for the cases of zigzag and cosine constrictions where Bloch stop-bands form in related periodic structures. (iii) The second subband being almost perfectly blocked by the constriction. (iv) Electron interactions favor intra-subband scattering while the non-interacting electron theory predicts predominance of inter-subband scattering. (v) Conductance quantization for the first few conductance steps being more pronounced for armchair constrictions but less so for zigzag constrictions. (vi) A much more prominent 2e 2 /h conductance plateau for the cosine constriction than is found in the absence of electron interactions. Possible implications for recent experiments are briefly discussed. arXiv:1206.4287v1 [cond-mat.mes-hall]

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“…12 A formation of a spatial spin polarization in a single quantum wire has been considered in Ref. [26] and it has been shown that this would result in hysteresis in electron transport measurements. However, all the calculated characteristics demonstrate the conventional coercive behavior.…”

Section: Resultsmentioning

confidence: 99%

Hysteretic phenomena in a 2DEG in the quantum Hall effect regime, studied in a transport experiment

et al. 2014

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We investigated experimentally non-equilibrium state of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime, studying the hysteresis of magnetoresistance of a 2DEG with a constriction. The large amplitude of the hysteresis enabled us to make the consistent phenomenological description of the hysteresis. We studied the dependence on the magnetic field sweep prehistory (minor loop measurements), recovered the anhysteretic curve, and studied the time dependence of the magnetoresistance. We showed that the hysteresis of magnetoresistance of a 2DEG in the QHE regime has significant phenomenological similarities with the hysteresis of magnetization of ferromagnetic materials, showing multistability, jumps of relaxation, and having the anhysteretic curve. Nevertheless, we revealed the crucial difference, manifested itself in an unusual inverted (anti-coercive) behavior of the magnetoresistance hysteresis. The time relaxation of the hysteresis has fast and slow regimes, similar to that of non-equilibrium magnetization of a 2DEG in QHE regime pointing to their common origin. We studied the dependence of the hysteresis loop area on the lithographic width of the constriction and found the threshold value of width ∼1.35 µm beyond which the hysteresis is not observed. This points to the edge nature of the non-equilibrium currents (NECs) and allows us to determine the width of the NECs area (∼0.5 µm). We suggest the qualitative picture of the observed hysteresis, based on non-equilibrium redistribution of the electrons among the Landau level states and assuming huge imbalance between the population of bulk and edge electronic states.

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Hysteresis and spin phase transitions in quantum wires in the integer quantum Hall regime

Cited by 20 publications

References 37 publications

First-principles study of electron transport in few-electron open quantum dots by the Hartree–Fock approach

First-principles study of electron transport in few-electron open quantum dots by the Hartree–Fock approach

Effect of electron-electron interactions on the electronic structure and conductance of graphene nanoconstrictions

Hysteretic phenomena in a 2DEG in the quantum Hall effect regime, studied in a transport experiment

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