Observation of Chiral Heat Transport in the Quantum Hall Regime

Granger, G.; Eisenstein, J. P.; Reno, John L.

doi:10.1103/physrevlett.102.086803

Cited by 100 publications

(132 citation statements)

References 14 publications

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“…However, no upstream heating had been observed at v ¼ 1 and v ¼ 2 (ref. 22) (as shown in Supplementary Fig. S4 and Supplementary Note S4); confirming that the observed heating is due to the presence of upstream neutral modes at certain fractional states.…”

Section: Discussionsupporting

confidence: 77%

Extracting net current from an upstream neutral mode in the fractional quantum Hall regime

et al. 2012

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Upstream neutral modes, counter propagating to charge modes and carrying energy without net charge, had been predicted to exist in some of the fractional quantum Hall states and were recently observed via noise measurements. Understanding such modes will assist in identifying the wavefunction of these states, as well as shedding light on the role of Coulomb interactions within edge modes. Here, operating mainly in the n ¼ 2/3 state, we place a quantum dot a few micrometres upstream of an ohmic contact, which serves as a 'neutral modes source'. We show that the neutral modes heat the input of the dot, causing a net thermo-electric current to flow through it. Heating of the electrons leads to a decay of the neutral mode, manifested in the vanishing of the thermo-electric current at T4110 mK. This set-up provides a straightforward method to investigate upstream neutral modes without turning to the more cumbersome noise measurements.

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Section: Discussionsupporting

confidence: 77%

Extracting net current from an upstream neutral mode in the fractional quantum Hall regime

et al. 2012

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“…The thermopower of a two-dimensional electron gas (2DEG) [1,2,3,4,5] has been attracting interest not only as a route to access its thermodynamic properties but also as a sensitive tool to probe various quantum phenomena that take place in a quantizing magnetic field (see, e.g., [6,7]). The thermopower in a 2DEG contains contributions from two separate mechanisms: diffusion and phonon drag.…”

Section: Introductionmentioning

confidence: 99%

Measurement of diffusion thermopower in the quantum Hall systems

Fujita¹,

Endo²,

Katsumoto³

et al. 2010

Physica E: Low-dimensional Systems and Nanostructures

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We have measured diffusion thermopower in a two-dimensional electron gas at low temperature (T =40 mK) in the field range 0 < B < 3.4 T, by employing the current heating technique. A Hall bar device is designed for this purpose, which contains two crossing Hall bars, one for the measurement and the other used as a heater, and is equipped with a metallic front gate to control the resistivity of the areas to be heated. In the low magnetic field regime (B ≤ 1 T), we obtain the transverse thermopower S yx that quantitatively agrees with the S yx calculated from resistivities using the generalized Mott formula. In the quantum Hall regime (B ≥ 1T), we find that S yx signal appears only when both the measured and the heater area are in the resistive (inter-quantum Hall transition) region. Anomalous gate-voltage dependence is observed above ∼1.8 T, where spin-splitting in the measured area becomes apparent.

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“…Thus charge transport due to these edge states might be observable over short distance scales, in relatively clean samples. It is also possible that they could be observed in thermal transport 34,35 .…”

Section: Introduction and Principal Resultsmentioning

confidence: 99%

“…This demonstrates that in bilayer graphene, one may or may not have edge states crossing zero energy for the same bulk spectrum, depending on boundary conditions. In the former case these are counterpropagating, so that no charge current is present at the edge in equilibrium, although these may transport energy 34 . That the presence or absence of low-energy edge excitations can depend on boundary conditions is somewhat unusual for a quantum Hall state, but is allowed because there are no strict quantum numbers distinguishing the counterpropagating states.…”

Section: B Variants On the Bilayer Zigzag Edgementioning

confidence: 99%

Edge states of bilayer graphene in the quantum Hall regime

2011

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We study the low energy edge states of bilayer graphene in a strong perpendicular magnetic field. Several possible simple boundaries geometries related to zigzag edges are considered. Tight-binding calculations reveal three types of edge state behaviors: weakly, strongly, and non-dispersive edge states. These three behaviors may all be understood within a continuum model, and related by nonlinear transformations to the spectra of quantum Hall edge-states in a conventional two-dimensional electron system. In all cases, the edge states closest to zero energy include a hole-like edge state of one valley and a particle-like state of the other on the same edge, which may or may not cross depending on the boundary condition. Edge states with the same spin generically have anticrossings that complicate the spectra, but which may be understood within degenerate perturbation theory. The results demonstrate that the number of edge states crossing the Fermi level in clean, undoped bilayer graphene depends both on boundary conditions and the energies of the bulk states.

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Observation of Chiral Heat Transport in the Quantum Hall Regime

Cited by 100 publications

References 14 publications

Extracting net current from an upstream neutral mode in the fractional quantum Hall regime

Extracting net current from an upstream neutral mode in the fractional quantum Hall regime

Measurement of diffusion thermopower in the quantum Hall systems

Edge states of bilayer graphene in the quantum Hall regime

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