Magnetic focusing in triangular electron billiards

Bøggild, Peter; Lindelöf, P. E.

doi:10.1103/physrevb.59.13067

Cited by 11 publications

(14 citation statements)

References 20 publications

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“…Depending on the geometrical symmetries of the QD, they can either follow stable periodic orbits, probe particular trajectories between the entrance and exit point contacts, or be reflected back into the entrance point contact. These classical ballistic effects can be predicted semiclassically or quantum mechanically and lead to large fluctuations of the magnetoconductance: [2][3][4][5] as the magnetic field is swept, the configuration of stable trajectories is modified, which affects the transmission through the QD.…”

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confidence: 99%

Long dephasing time and high-temperature conductance fluctuations in an open InGaAs quantum dot

et al. 2002

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We measure the electron phase-coherence time up to 18 K using universal fluctuations in the lowtemperature magnetoconductance of an open InGaAs quantum dot. The temperature dependence of is quantitatively consistent with the two-dimensional model of electron-electron interactions in disordered systems. In our sample, is two to four times larger than previously reported in GaAs quantum dots. We attribute this enhancement to a larger value of the Fermi energy and the lower electron effective mass in our sample. We also observe a distinct type of conductance fluctuation due to ballistic electron focusing inside the dot up to 204 K.Since the pioneering work of Marcus and co-workers, 1 open ballistic quantum dots ͑QDs͒ have mainly been used as tools to investigate two main issues: ballistic electron dynamics and electron decoherence. When their mean free path becomes larger than the lateral dimensions of the QD, electrons can be viewed semiclassically as billiard balls. Depending on the geometrical symmetries of the QD, they can either follow stable periodic orbits, probe particular trajectories between the entrance and exit point contacts, or be reflected back into the entrance point contact. These classical ballistic effects can be predicted semiclassically or quantum mechanically and lead to large fluctuations of the magnetoconductance: 2-5 as the magnetic field is swept, the configuration of stable trajectories is modified, which affects the transmission through the QD.On the other hand, electron decoherence is mainly probed thanks to the emergence of two quantum corrections to the magnetoconductance, weak localization ͑WL͒ and universal conductance fluctuations ͑UCFs͒, arising from quantum interferences between trajectories inside the QD. As interferences only occur when phase coherence is maintained over the trajectory length, WL and UCFs give also access to the measurement of the electron phase-coherence time . [6][7][8][9] In GaAs/AlGaAs open QDs, it was shown 10,11 that the dephasing rate Ϫ1 is the sum of two electron-electron ͑e-e͒ scattering rates: a large energy-transfer scattering mechanism with a rate ee Ϫ1 , and a small energy-transfer ͑Nyquist͒ mechanism with a rate N Ϫ1 . The temperature dependence of Ϫ1 was found to be qualitatively consistent with the theoretical expression established for disordered two-dimensional ͑2D͒ electron systems: 10,12,13where E F is the Fermi energy, F is the Fermi wavelength, and l is the mean free path. However, a quantitative agreement with experimental data was only found for an arbitrary value of l , one order-of-magnitude smaller than l measured in the two-dimensional electron gas ͑2DEG͒. At very low temperatures, (T) deviates from the above temperature dependence and an unexplained saturation of is observed. 11,14 In the present work, we analyze magnetoconductance fluctuations arising from both phase-coherent and classical focusing effects in an InGaAs/InAlAs open circular QD over a wide temperature range ͑from 1.3 to 204 K͒. is extracted up to 18 K from the amplitu...

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Long dephasing time and high-temperature conductance fluctuations in an open InGaAs quantum dot

et al. 2002

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“…We parameterized the chaotic strength and its stability in the form of normalized three particle correlator r 3 which touch to chaotic limit (two) for completely chaotic and undeviating system. The normalized correlator r 3 isolated the phase and the effect of resonance decay and it is precisely correlated with the chaotic and coherence fractions for the static sources [25,[30][31][32][33]. In our model calculations the chaotic intercept Λ 2 (k 1 , k 2 ) for the correlations of two particles when their corresponding relative momentum approaches to zero can represented as…”

Section: A Normalized Three Particle Correlatormentioning

confidence: 99%

Effects of Heat Transfer Analysis Through Boson Femtoscopy with Fraction Order Differentiation

Bary¹,

Ahmed²,

Sajid³

et al. 2021

Preprint

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Higher order femtoscopy measured to examine the heat exchanger characterization of the fluid debris produced in the collisions and investigated a remarkable suppression in the bosons interferences measurement. The analogous suppression can be analyzed to explore the coherence of boson thermal particle production sources at unprecedented energies. We illustrate the particles emissions from radiated sources with statistical coherence which induce the thermal particles interferences to probe the peculiarity of the heated sources as well as the distinctions about the heat exchangers in the collisions at higher temperature. We perspicacious that the bosons seem to the pertinent aspirant of heat exchanger, and the normalized three particles correlators evaluate the existence of such hybrid phases significantly. The key point of this research is that we analyze the three particles correlations with their normalized correlations by difference equations to determine the characteristics of heat exchanger and its applications. With such distinctive and efficient approach, we observe a significant difference in the correlation functions at higher temperature and momenta regimes.

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“…A wide point contact produces an electron beam with approximately a cos(α) angular distribution where α is the angle from perpendicular injection [9]. Despite this, at fields meeting the focusing condition a high percentage of the electrons converge on the collector [9]. These electrons, launched at different angles, traverse paths of different lengths and result in a distribution of transit times.…”

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“…Group velocity dispersion was calculated to be only 2ps for a 1ps pulse injected into the transport region. A wide point contact produces an electron beam with approximately a cos(α) angular distribution where α is the angle from perpendicular injection [9]. Despite this, at fields meeting the focusing condition a high percentage of the electrons converge on the collector [9].…”

mentioning

confidence: 99%

“…These electrons, launched at different angles, traverse paths of different lengths and result in a distribution of transit times. A classical analysis [9] was used to model the resulting time response to a 1ps emitter current pulse. Assuming all carriers move at the Fermi velocity, and using the geometry of Fig.1b, a response width of approximately 18ps was predicted.…”

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Picosecond Time-Resolved Two-Dimensional Ballistic Electron Transport

Shaner

Lyon

2004

Phys. Rev. Lett.

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Time-resolved transport of ballistic electrons in a two-dimensional electron gas has been measured with a resolution of less than 5ps. This was accomplished by using picosecond electrical pulses to launch electrons from the emitter of a transverse magnetic focusing structure and optoelectronically sampling the collector voltage. Both plasma resonances and the ballistic transport signal are clearly resolved. The transit time appears to be somewhat longer than expected from simple Fermi velocity considerations.

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Magnetic focusing in triangular electron billiards

Cited by 11 publications

References 20 publications

Long dephasing time and high-temperature conductance fluctuations in an open InGaAs quantum dot

Long dephasing time and high-temperature conductance fluctuations in an open InGaAs quantum dot

Effects of Heat Transfer Analysis Through Boson Femtoscopy with Fraction Order Differentiation

Picosecond Time-Resolved Two-Dimensional Ballistic Electron Transport

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