Electron waveguide interferometers for spin‐dependent transport experiments

Chiatti, Olivio; Buchholz, Sven S.; Kunze, U.; Reuter, D.; Wieck, A. D.; Fischer, Saskia F.

doi:10.1002/pssb.201350229

Cited by 2 publications

(4 citation statements)

References 101 publications

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“…The question that arises is how the mode-dependent heat transfer evolves in networks of extended 1D waveguides, where phase-coherent effects have been investigated inand out-of-equilibrium. 8,9 Here, we perform cross-correlated electronic noise measurements to determine the charge carrier temperature in an extended 1D waveguide network made from an Al-GaAs/GaAs heterostructure. We investigate the heat transport through an asymmetric quantum ring, 9 which is a network of 1D electron waveguides with 2D contacts as depicted in Fig.…”

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confidence: 99%

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Mode-selected heat flow through a one-dimensional waveguide network

Riha

Miechowski

Buchholz

et al. 2015

Applied Physics Letters

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Cross-correlated measurements of thermal noise are performed to determine the electron temperature in nanopatterned channels of a GaAs/AlGaAs heterostructure at 4.2 K. Two-dimensional (2D) electron reservoirs are connected via an extended one-dimensional (1D) electron waveguide network. Hot electrons are produced using a current I h in a source 2D reservoir, are transmitted through the ballistic 1D waveguide and relax in a drain 2D reservoir. We find that the electron temperature increase ∆T e in the drain is proportional to the square of the heating current I h , as expected from Joule's law. No temperature increase is observed in the drain when the 1D waveguide does not transmit electrons. Therefore, we conclude that electron-phonon interaction is negligible for heat transport between 2D reservoirs at temperatures below 4.2 K. Furthermore, mode control of the 1D electron waveguide by application of a top-gate voltage reveals that ∆T e is not proportional to the number of populated subbands N , as previously observed in single 1D conductors. This can be explained with the splitting of the heat flow in the 1D waveguide network.The transport properties of a one-dimensional (1D) waveguide are dominated by the wave-like character of electrons. The nanoscale confinement potential is typically created by applying advanced lithographic methods to high mobility two-dimensional electron gases (2DEGs). In ballistic 1D waveguides electric conductance quantization is observed 1,2 and is shown to scale linearly with the thermal conductance at low temperatures.3-5 This indicates the validity of the WiedemannFranz relation in the ballistic 1D regime, when electronphonon and electron-electron interactions can be neglected. 6,7 In previous works by van Houten et al. 3 and Chiatti et al.4 comparable heating measurements between two AlGaAs/GaAs 2DEGs were performed. The two 2DEGs were connected via a single quantum point contact (QPC) and the increase in electron temperature ∆T e of the indirectly heated 2D reservoir was measured by a second QPC. ∆T e was found to be proportional to the number of populated subbands N of the QPC. The question that arises is how the mode-dependent heat transfer evolves in networks of extended 1D waveguides, where phase-coherent effects have been investigated inand out-of-equilibrium. 8,9Here, we perform cross-correlated electronic noise measurements to determine the charge carrier temperature in an extended 1D waveguide network made from an AlGaAs/GaAs heterostructure. We investigate the heat transport through an asymmetric quantum ring, 9 which is a network of 1D electron waveguides with 2D contacts as depicted in Fig. 1. A global top-gate enables the control of the conductivity of the 2D reservoirs and the 1D electron waveguides. One electron reservoir is heated above the lattice temperature via the current heating a) E-mail: riha@physik.hu-berlin.de technique.10 The increase in electron temperature ∆T e of the other electron reservoir is extracted by the means of Johnson-Nyquist noise thermometr...

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confidence: 99%

“…8,9 Here, we perform cross-correlated electronic noise measurements to determine the charge carrier temperature in an extended 1D waveguide network made from an Al-GaAs/GaAs heterostructure. We investigate the heat transport through an asymmetric quantum ring, 9 which is a network of 1D electron waveguides with 2D contacts as depicted in Fig. 1.…”

mentioning

confidence: 99%

Mode-selected heat flow through a one-dimensional waveguide network

Riha

Miechowski

Buchholz

et al. 2015

Applied Physics Letters

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“…This is achieved by further lateral confinement using nanopatterning. In such way, 1D structures such as high‐quality quantum point contacts (QPCs), elongated quantum wires (QWRs), quantum rings (QRs), and other extended waveguide structures () can be fabricated. Operation of future quantum device circuits will require a full control of the phase coherence.…”

Section: Introductionmentioning

confidence: 99%

“…For example, non‐symmetrically applied electrical currents in attached reservoirs (heat baths) easily lead to thermal gradients across such nanoscale device structures. This will decrease the charge carrier mobility () and phase coherence length (). Therefore, a full knowledge of thermal and charge transport under thermal non‐equilibrium is required.…”

Section: Introductionmentioning

confidence: 99%

Heat flow, transport and fluctuations in etched semiconductor quantum wire structures

Riha

Chiatti

Buchholz

et al. 2016

Physica Status Solidi (a)

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Low‐dimensional transport in semiconductor meso‐ and nanostructures is a topical field of fundamental research with potential applications in future quantum devices. However, thermal non‐equilibrium may destroy phase‐coherence and remains to be explored experimentally. Here, we present effects of thermal non‐equilibrium in various implementations of low‐dimensional (non‐interacting) electron systems, fabricated by etching AlGaAs/GaAs heterostructures. These include narrow quasi‐two‐dimensional (2D) channels, quasi‐one‐dimensional (1D) waveguide networks, quantum rings (QRs), and single 1D constrictions, such as quantum point contacts (QPCs). Thermal non‐equilibrium is realized by current heating. The charge carrier temperature is determined by noise thermometry. The electrical conductance and the voltage–noise are measured with respect to bath temperatures, heating currents, thermal gradients, and electric fields. We determine and discuss heat transport processes, electron‐energy loss rates, and electron–phonon interaction, and our results are consistent with the Wiedemann–Franz relation. Additionally, we show how non‐thermal current fluctuations can be used to identify electric conductance anomalies due to charge states.

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Electron waveguide interferometers for spin‐dependent transport experiments

Cited by 2 publications

References 101 publications

Mode-selected heat flow through a one-dimensional waveguide network

Mode-selected heat flow through a one-dimensional waveguide network

Heat flow, transport and fluctuations in etched semiconductor quantum wire structures

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