Magnetic delocalisation of a two-dimensional electron gas and the quantum law of electron-electron scattering

Uren, Michael J.; Davies, R A; Kaveh, M.; Pepper, M.

doi:10.1088/0022-3719/14/13/003

Cited by 84 publications

(25 citation statements)

References 19 publications

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“…The obtained phase coherence time Τφ = 29.7 ps due to inelastic scattering is much larger than τt . A prefactor α = 0.25 ± 0.03 is obtained which is smaller than the values between 0.5 and 1 as predicted by theory [6], but is in agreement with estimations of the WL effect from experiments on Si inversion layers [7] and GaAs/AlGaAs heterostructures [8]. The Cooperon gives a positive MR contribution at small magnetic fields, but according to our fit, this part is smaller than ten per cent of the WL effect.…”

supporting

confidence: 86%

Weak Localization and Electron-Electron Interaction in Si/SiGe Quantum Wells

et al. 1995

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A negative magnetoresistance is observed in Si/SiGe modulation doped heterostructures which is attributed to the single particle quantum interference (weak localization) effect. From analysis of the experimental data the electron phase coherence time τφ is extracted to follow a (αT + bΤ2 ) -1 dependence. The evaluated prefactor α = 0.25 is below the theoretical limit of 0.5, but agrees with observations in Si and GaAs/AlGaAs heterostructures.PACS numbers: 73.20.Fz Advances in epitaxial growth techniques of Si/Si 1-x Gex heterostuctures have resulted in high-mobility twodimensional electron (2DEG) and hole gases [1,2]. These heterostructures are of considerable importance for possible device applications. Since the carrier mobilities in modulation doped Si/Si1-x Gex samples available exceed those of Si metal-oxide semiconductor (MOS) devices by far, studies of carrier transport which were previously restricted mainly to the GaAs/Ga1-xΑlxΑs system can now be performed in Si based systems.Magnetotransport measurements on Si/SiGe heterostuctures were performed in order to investigate the effects of weak localization (WL) and electron-electron interaction (EEI). Applying the theories of WL for 2D systems, we have extracted from the data the temperature dependence of the phase-breaking time τφ and the prefactor α.The Si/Si1-x Gex heterostucture M4 was grown at 550°C on high resistivity p -substrates using an ultrahigh-vacuum chemical vapor deposition (UHV-CVD) system. A 500 nm thick Si/Si1-xGex superlattice buffer with an average Ge content of 0.3 is grown to serve as a strain relief multi-layer [2]. Above the superlattice (SL) a partly relaxed 50 nm thick Si 0.7Ge0.3 alloy buffer is grown, followed *This work is supported by "Fonds zur Förderung der wissensch. Forschung" Austria.(873)

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confidence: 86%

Weak Localization and Electron-Electron Interaction in Si/SiGe Quantum Wells

et al. 1995

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“…[ 62,63 ]. The experimentally established negative magnetoresistance in Si-MOSFET 64,65,66,67 was also analyzed from the TQC point of view. Characteristic sizes of the selfcrossing trajectories, phase relaxation time of the electron wave function due to electron-electron and electronphonon collisions, and the electron-electron coupling constant in the diffusive channel were determined.…”

Section: Metal-insulator Transition In Two-dimensional Systemsmentioning

confidence: 99%

Quantum phase transitions in two-dimensional systems

Shangina

Dolgopolov

2003

Phys.-Usp.

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“…where p ¼ 1 for a 2D system [1] and p ¼ 2 3 for a 1D system [43]. In our device, p ¼ 1 gives the best fitting, as shown in Fig.…”

Section: Temperature Dependencementioning

confidence: 56%

“…Quantum interference, one of the most remarkable effects of quantum mechanics, arising from the wave nature of particles has led to some celebrated results in mesoscopic systems, including weak localization in two-dimensional (2D) systems [1,2], Aharonov-Bohm oscillations in ring structures [3,4], sharp peaks in magnetoresistance in chaotic cavities [5,6], etc. Among its various applications, quantum interference has been used successfully as a tool to investigate properties of particles such as monitoring correlation and entanglement as demonstrated in MachZehnder interferometery [7,8], Aharonov-Bohm interferometery [9,10], Hanbury Brown-Twiss interferometery [11,12], and the electronic analogue of the Hong-OuMandel device [13,14].…”

Section: Introductionmentioning

confidence: 99%

Interference Effects in a Tunable Quantum Point Contact Integrated with an Electronic Cavity

et al. 2017

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We show experimentally how quantum interference can be produced using an integrated quantum system comprising an arch-shaped short quantum wire (or quantum point contact, QPC) of 1D electrons and a reflector forming an electronic cavity. On tuning the coupling between the QPC and the electronic cavity, fine oscillations are observed when the arch QPC is operated in the quasi-1D regime. These oscillations correspond to interference between the 1D states and a state which is similar to the Fabry-Perot state and suppressed by a small transverse magnetic field of AE60 mT. Tuning the reflector, we find a peak in resistance which follows the behavior expected for a Fano resonance. We suggest that this is an interesting example of a Fano resonance in an open system which corresponds to interference at or near the Ohmic contacts due to a directly propagating, reflected discrete path and the continuum states of the cavity corresponding to multiple scattering. Remarkably, the Fano factor shows an oscillatory behavior taking peaks for each fine oscillation, thus, confirming coupling between the discrete and continuum states. The results indicate that such a simple quantum device can be used as building blocks to create more complex integrated quantum circuits for possible applications ranging from quantum-information processing to realizing the fundamentals of complex quantum systems.

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Magnetic delocalisation of a two-dimensional electron gas and the quantum law of electron-electron scattering

Cited by 84 publications

References 19 publications

Weak Localization and Electron-Electron Interaction in Si/SiGe Quantum Wells

Weak Localization and Electron-Electron Interaction in Si/SiGe Quantum Wells

Quantum phase transitions in two-dimensional systems

Interference Effects in a Tunable Quantum Point Contact Integrated with an Electronic Cavity

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