Note on the Wiedemann-Franz law and the Mott rule in two-dimensional systems in strong magnetic fields

Grünwald, Annette; Hajdu, János

doi:10.1007/bf01304443

Cited by 7 publications

(5 citation statements)

References 5 publications

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“…Subsequently, we make use of special features of the electronic transport in lowlintermediate magnetic fields and derive the more convenient approximate formulae of the Lifshits-Kosevich type utilizing the Poisson summation formula. The numerical examples illustrating the energy and field dependence of approximate expressions will be given and the limits of the validity of the Wiedemann-Franz law and Mott rule, recently discussed in [4], investigated.…”

Section: Introductionmentioning

confidence: 99%

Quantum Oscillations of Thermogalvanomagnetic Coefficients in Two‐Dimensional Electron Systems

Havlova

Smrčka

1986

Physica Status Solidi (b)

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Based on the one-electron version of the Kubo formula and assuming only the elastic scattering of carriers on static impurities the quantum oscillations of the transport coefficients are evaluated of two-dimensional electron systems in weak/intermediate magnetic fields. The changes in the oscillating pattern due to the variation of the magnetic field, the carrier density, and the temperature are investigated. Numerical examples give results in qualitative agreement with recent experimental data.Auf der Grundlage der Einelektronenversion der Kuboformel und unter der Annahmc nur elastischer Streuung der Trager an den statischen Storstellen werden die Quantenoszillationen der Transportkoeffizienten von zweidimensionalen Elektronensystemen in schwachen/mittleren Magnetfeldern berechnet. Es werden die h d e r u n g e n im Oszillationsbild, die durch die Variationen des Magnetfeldes, der Tragerdichte und der Temperatur veruSsacht werden, untersucht. Numerische Beispiele bringen Ergebnisse, die sich in qualitativer Ifbereinstimmung rnit den unlangst publizierten experimentellen Daten befinden.

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Section: Introductionmentioning

confidence: 99%

Quantum Oscillations of Thermogalvanomagnetic Coefficients in Two‐Dimensional Electron Systems

Havlova

Smrčka

1986

Physica Status Solidi (b)

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“…II, the offdiagonal elements 76,77 similarly arise from the magnon counter-current by the thermally-induced magnetization gradient [71][72][73][78][79][80] …”

Section: Hall Conductances Of Magnonsmentioning

confidence: 99%

“…( 3), the contribution from each magnon K σ to the total thermal conductance of the AF K AF becomes Eq. ( 6) in terms of Onsager coefficients where the off-diagonal elements 76,77 arise from the magnetization gradient-induced counter-current. This is in analogy to thermal transport of electrons in metals 74 where, however, the off-diagonal contributions are strongly suppressed by the sharp Fermi surface of fermions at temperatures k B T much smaller than the Fermi energy.…”

Section: Antiferromagnetmentioning

confidence: 99%

“…In this sense, it can be concluded that the linear-in-T behavior of the thermomagnetic ratio is indeed universal. We remark that if one wrongly omits the off-diagonal coefficients 76,77 in Eq. ( 6) which can be as large as the diagonal ones, the ratio would not obey WF law, breaking the linearity in temperature.…”

Section: Antiferromagnetmentioning

confidence: 99%

“…where as we have seen in Sec. II, the offdiagonal elements 76,77 similarly arise from the magnon counter-current by the thermally-induced magnetization gradient [71][72][73][78][79][80] [46] for details of the thermal Hall conductance in the 'quantum' Hall regime and the Hall coefficient L yx ij↑ . In the almost flat band E * 0↑ ≈ E * 0↓ ≡ E * 0 , the Hall transport coefficient Eq.…”

Section: Hall Conductances Of Magnonsmentioning

confidence: 99%

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Magnonic topological insulators in antiferromagnets

et al. 2017

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Extending the notion of symmetry protected topological phases to insulating antiferromagnets (AFs) described in terms of opposite magnetic dipole moments associated with the magnetic Néel order, we establish a bosonic counterpart of topological insulators in semiconductors. Making use of the Aharonov-Casher effect, induced by electric field gradients, we propose a magnonic analog of the quantum spin Hall effect (magnonic QSHE) for edge states that carry helical magnons. We show that such up and down magnons form the same Landau levels and perform cyclotron motion with the same frequency but propagate in opposite direction. The insulating AF becomes characterized by a topological Z2 number consisting of the Chern integer associated with each helical magnon edge state. Focusing on the topological Hall phase for magnons, we study bulk magnon effects such as magnonic spin, thermal, Nernst, and Ettinghausen effects, as well as the thermomagnetic properties of helical magnon transport both in topologically trivial and nontrivial bulk AFs and establish the magnonic Wiedemann-Franz law. We show that our predictions are within experimental reach with current device and measurement techniques.

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Calculations of Magnetotransport Properties of InSb Bicrystals with Several Populated Q2D Subbands

Nachtwei

Schulze

Gobsch

et al. 1988

Physica Status Solidi (b)

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Dedicated to Prof. Dr. E. GUTSCHE on the occasion of his 60th birthdayThe magnetic subband structure of the quasi two-dimensional electron gas in an inversion layer with several populated electric subbands in InSb bicrystals is calculated using a straightforward and accurate method developed recently. The oscillating part of the magnetoresistance and the magnetic field dependence of the Hall resistance are evaluated by using the Ando model. Two different assumptions concerning the Fermi level position in dependence on the magnetic field are presented and discussed. A good description of the magnetotransport data determined in previous experiments is achieved. It is shown that the simple model of 8-like Landau energy levels and the resulting discontinous magnetic field dependence of the Fermi energy for a fixed inversion electron density is not able t o describe the magnetotransport behaviour determined in the experiments. Estimates of the electron mobilit,ies in the electric subbands from the Landau level broadening lead us to the conclusion that the mobilities obtained from the onset of the Shubnikovde Haas-oscillations are lower limits.Die magnetische Subbandstruktur fur ein quasi-zweidimensionales Elektronengas einer Inversionsschicht mit mehreren besetzten elektrischen Subbandern in InSb-Bikristallen wird mit Hilfe einer einfachen Methode berechnet. Die oszillierenden Anteile des Magnetowiderstandes und des Hallwiderstandes werden unter Verwendung des Ando-Modells bestimmt. Zwei verschiedene Annahmen zur Lage der Fermienergie in Abhangigkeit vom Magnetfeld werden vorgestellt und diskutiert.Eine gute Beschreibung der experimentellen Ergebnisse wird erreicht. Es wird gezeigt, daR das einfache Model1 mit 8-formigen Landauenergieniveaus und der daraus resultierenden oszillierenden Fermienergie bei fester Flachenladung keine geeignete Interpretation der experimentellen Ergebnisse gestattet. AbschMzungen der Elektronenbeweglichkeiten in den Subbiindern aus der Verbreiterung der Landauniveaus ergeben, daB die aus den Einsatzkanten der Shnbnikov-de Haas-Oszilletionen ermittelten Beweglichkeiten als minimale Werte angesehen werden konnen. l )

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Note on the Wiedemann-Franz law and the Mott rule in two-dimensional systems in strong magnetic fields

Cited by 7 publications

References 5 publications

Quantum Oscillations of Thermogalvanomagnetic Coefficients in Two‐Dimensional Electron Systems

Quantum Oscillations of Thermogalvanomagnetic Coefficients in Two‐Dimensional Electron Systems

Magnonic topological insulators in antiferromagnets

Calculations of Magnetotransport Properties of InSb Bicrystals with Several Populated Q2D Subbands

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