Two-level model for the generation and relaxation of hot electrons near the breakdown of the quantum Hall effect

Güven, Kaan; Gerhardts, Rolf R.; Kaya, İsmet I.; Sagol, B.E.; Nachtwei, G.

doi:10.1103/physrevb.65.155316

Cited by 24 publications

(30 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11 This model is based on the well-established assumption of the presence of potential fluctuations ͑mainly due to charged impurities͒. 4 These fluctuations provide localization centers for electrons and holes in the Landau levels and lead to locally enhanced electric fields.…”

Section: ͒mentioning

confidence: 99%

Time scale of the excitation of electrons at the breakdown of the quantum Hall effect

et al. 2002

View full text Add to dashboard Cite

We have investigated the time scale of the excitation of electrons leading to a transition from the quantum Hall ͑QH͒ state to the dissipative state in the two-dimensional electron systems of GaAs/AlGaAs heterostructures. The measurements were performed by applying nanosecond electric pulses to the current contacts of QH devices having various electron mobilities (1ϫ10 5 р H р9ϫ10 5 cm 2 /V s) at integer filling factors ϭ2, 4, and 6. The breakdown of the quantum Hall effect ͑QHE͒ occurs when the applied pulses exceed a critical pulse width t p c that is a function of pulse amplitude, magnetic field, and electron mobility (0.4рt p c р18 ns). By applying a simple drift model, we obtain an estimate for the critical drift lengths, which vary from about 1 to 25 m. No general differences of the response to short electric pulses have been found between Hall bar and Corbino devices. We interpret the critical times as drifting times between inelastic scattering events, and the critical lengths as related to the inelastic scattering lengths ᐉ in of electrons causing the QHE breakdown. Characteristic dependences of the critical drift times and lengths on the amplitude, filling factor, and the mobility have been observed and can be attributed to impurity-assisted inter-Landau-level tunneling.

show abstract

Section: ͒mentioning

confidence: 99%

Time scale of the excitation of electrons at the breakdown of the quantum Hall effect

et al. 2002

View full text Add to dashboard Cite

show abstract

“…This screening scenario has been established some time ago 1,2 and was applied, e.g., to calculate, at zero temperature, the electronic DOS 3 and transport 4,5 through 2DEGs in smooth periodic and random potentials. The explanation 6,7 of several experimental results, e.g., on quantum Hall devices under high currents close to the breakdown of the quantized Hall effect, 8,9 rely also on these ideas. A systematic investigation of these interesting nonlinear screening effects is, however, apparently not available in the literature.…”

Section: Introductionmentioning

confidence: 99%

Thomas-Fermi-Poisson theory of screening for laterally confined and unconfined two-dimensional electron systems in strong magnetic fields

Siddiki¹,

Gerhardts²

2003

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

We examine within the self-consistent Thomas-Fermi-Poisson approach the low-temperature screening properties of a two-dimensional electron gas (2DEG) subjected to strong perpendicular magnetic fields. Numerical results for the unconfined 2DEG are compared with those for a simplified Hall bar geometry realized by two different confinement models. It is shown that in the strongly non-linear screening limit of zero temperature the total variation of the screened potential is related by simple analytical expressions to the amplitude of an applied harmonic modulation potential and to the strength of the magnetic field.

show abstract

“…So far, we can explain certain aspects of these observations by a simple drift model [22,24] and by a twolevel model [25,26]. Our results show clearly that the current flow in QHSs must contain local contributions [20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 70%

“…In these real-time domain measurements, we found excitation times of 3 ns ≤ t exc ≤ 30 ns [35][36][37]. From thermodynamic considerations it was concluded that t rel ≤ t exc holds [25]. Thus, the values for t exc measured in the real-time domain could be interpreted as a confirmation of the order of magnitude for c P t measured using the time-integrating method.…”

Section: Introductionmentioning

confidence: 79%

“…The applicability of such detectors is, however, limited by their rather complicated operation parameters (temperatures at or below 4.2 K, B ≈ 5 T). The time evolution of the photosignals was modelled by a twolevel model which is able to describe the experimental observations qualitatively (in some cases even quantitatively) [25,26]. To provide more easily achieved operation conditions for QH THz detectors, we prepared Corbino-shaped devices on wafers with HgTe quantum wells, embedded within HgCdTe barriers.…”

Section: Optically Induced Dissipation In Qhssmentioning

confidence: 99%

See 1 more Smart Citation

Optically and electrically induced dissipation in quantum Hall systems

Nachtwei

Stellmach

Vasile

et al. 2008

Physica Status Solidi (b)

View full text Add to dashboard Cite

IntroductionThe quantum Hall effect (QHE) [1] is interesting with respect to understanding its physical mechanisms and with respect to its applications. Besides the use of the QHE to maintain a resistance standard on the basis of a macroscopic quantum effect [2], it is also possible to use quantum Hall systems (QHSs) to detect THz waves. This is because the energy gap between adjacent Landau levels (LLs) of ∆E LL ≈ 10 meV corresponds to photons of electromagnetic waves with a wavelength of λ ≈ 125 µm. Thus, sensitive and fast THz detectors with spectral selectivity [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] can be made on the basis of QHSs. However, it takes effort to cool the samples to temperatures at or below 4.2 K and to expose the samples to magnetic fields of typically B > 4 T. As this requires helium cooling of the samples and the application of superconducting magnets, QH THz detectors are not particularly appropriate for widespread use. These detectors have, however, the unique simultaneous properties of high sensitivity,

show abstract

Two-level model for the generation and relaxation of hot electrons near the breakdown of the quantum Hall effect

Cited by 24 publications

References 19 publications

Time scale of the excitation of electrons at the breakdown of the quantum Hall effect

Time scale of the excitation of electrons at the breakdown of the quantum Hall effect

Thomas-Fermi-Poisson theory of screening for laterally confined and unconfined two-dimensional electron systems in strong magnetic fields

Optically and electrically induced dissipation in quantum Hall systems

Contact Info

Product

Resources

About