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Wyszukujesz frazę "Eaves, L." wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
Breakdown of the Dissipationless Quantum Hall State: Quantised Steps and Analogies with Classical and Quantum Fluid Dynamics
Autorzy:
Eaves, L.
Powiązania:
https://bibliotekanauki.pl/articles/2027463.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.43.Jn
73.43.Cd
73.61.Ey
Opis:
The breakdown of the integer quantum Hall effect at high currents sometimes occurs as a series of regular steps in the dissipative voltage drop measured along the Hall bar. The steps were first seen clearly in two Hall bars used to maintain the US Resistance Standard, but have also been reported in other devices. It is proposed that the origin of the steps can be understood in terms of an instability in the dissipationless flow at high electron drift velocities. The instability is induced by impurity- or defect-related inter-Landau level scattering processes in local microscopic regions of the Hall bar. Electron-hole pairs (magneto-excitons) are generated in the quantum Hall fluid in these regions and that the electronic motion can be envisaged as a quantum analogue of the von Karman vortex street which forms when a classical fluid flows past an obstacle.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 205-212
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theory of Magnetotunnelling through Donors in the Quantum Well of Double-Barrier Resonant-Tunnelling Structures
Autorzy:
Fromhold, T. M.
Sheard, F. W.
Eaves, L.
Powiązania:
https://bibliotekanauki.pl/articles/1921661.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
71.55.Eq
85.30.Tv
Opis:
The tunnel current from a two-dimensional electron gas (2DEG) into donor impurities in the quantum well of a double-barrier heterostructure is studied using the Bardeen Transfer-Hamiltonian formalism. Resonant tunnelling occurs when the donor level lies within the energy range of occupied 2DEG states. It is shown that in the presence of a magnetic field B normal to the current flow, the magnetocurrent J(B) is determined by the Fourier probability density of the donor wave function corresponding to the momentum p0 transferred to the tunnelling electrons by the Lorentz force. Then experimental J(B) curves, in principle, directly measure the donor wave function. The magnetocurrent is quenched when p0 greatly exceeds the width of the distribution of momentum Fourier components of the donor wave function.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 737-740
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Pressure Magnetotransport Measurements of Resonant Tunnelling via X-Minimum Related States in AlAs Barrier
Autorzy:
Gryglas, M.
Przybytek, J.
Baj, M.
Eaves, L.
Henini, M.
Powiązania:
https://bibliotekanauki.pl/articles/2028835.pdf
Data publikacji:
2001-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.43.Jn
73.63.Hs
Opis:
In this paper, we present the results of magnetotransport experiments performed on a single barrier GaAs/AlAs/GaAs heterostructures. Tunnel current was measured as a function of magnetic field for different values of bias voltage and hydrostatic pressure. We observed that the amplitude of the magnetooscillations of tunnel current quenched when the requirements for resonant tunnelling were met and it recovered in out-of-resonance conditions. This effect was observed both for tunnelling through donor states and through X-minimum related quasiconfined conduction band states. The fact that also in the latter case the amplitude was restored suggests that this process involved X$\text{}_{z}$ subbands and took place without a participation of phonons (the so-called k$\text{}_{ǁ}$-conserving process).
Źródło:
Acta Physica Polonica A; 2001, 100, 3; 403-408
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Tunnelling Studies of Chaos in Quantised Systems
Autorzy:
Eaves, L.
Fromhold, T. M.
Wilkinson, P. P.
Sheard, F. W.
Powiązania:
https://bibliotekanauki.pl/articles/1967958.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.My
73.40.Gk
85.30.Mn
05.45.+b
Opis:
This paper gives a brief introductory overview of quantum chaology, with particular reference to recent experimental work involving the use of semiconductor heterostructures. In the presence of a tilted magnetic field, a double-barrier resonant-tunnelling device incorporating a quantum well produces a chaotic stadium for electron motion. The basic properties of this system are described. It is shown how resonant magnetotunnelling spectroscopy provides firm experimental evidence for the effect of scarred wave functions on a physically-measurable property, in this case the measured current-voltage characteristics of the device. The paper concludes with some speculations concerning for the development of this field.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 609-619
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Capacitance Spectroscopy of Single-Barrier GaAs/AlAs/GaAS Structures Containing InAs Quantum Dots
Autorzy:
Belyaev, A. E.
Eaves, L.
Main, P. C.
Polimeni, A.
Stoddart, S. T.
Henini, M.
Powiązania:
https://bibliotekanauki.pl/articles/1969042.pdf
Data publikacji:
1998-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
85.30.Mn
Opis:
An electrostatic profile of single-barrier heterostructures with InAs quantum dots encased into barrier has been studied. The role of growth conditions and structure's design is investigated. The charging state and position of energy levels for InAs quantum dots embedded in AlAs matrix are discussed.
Źródło:
Acta Physica Polonica A; 1998, 94, 2; 245-249
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum States of Self-Assembled InAs Dots Probed by Magneto-Tunneling Spectroscopy
Autorzy:
Patanè, A.
Eaves, L.
Main, P. C.
Levin, A.
Zambrano, M. L.
Henini, M.
Vdovin, E. E.
Dubrovskii, Y. V.
Hill, G.
Powiązania:
https://bibliotekanauki.pl/articles/2027456.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.-b
73.63.Kv
73.43.Jn
Opis:
We present an experimental study of the electron wave function in InAs/GaAs self-assembled quantum dots. Magneto-tunneling spectroscopy is employed as a non-invasive probe to produce two-dimensional images of the probability density of an electron confined in a quantum dot. The images reveal the elliptical symmetry of the ground state and the characteristic lobes of the higher energy states of the dots.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 165-173
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Breakdown of the Quantum Hall Effect
Autorzy:
Maude, D. K.
Rigal, L. B.
Desrat, W.
Potemski, M.
Portal, J. C.
Eaves, L.
Wasilewski, Z. R.
Toropov, A. I.
Hill, G.
Powiązania:
https://bibliotekanauki.pl/articles/2027467.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Pm
74.25.Dw
Opis:
The breakdown of the dissipationless conductance in the integer and fractional quantum Hall effect regime is reviewed. The temperature dependence of the critical current and of the critical magnetic field at breakdown bears a striking resemblance to the phase diagram of the phenomenological two-fluid Gorter-Casimir model for superconductivity. In addition, a remarkably simple scaling law exists between different filling factors.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 213-226
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stochastic Carrier Dynamics in Semiconductor Superlattices
Autorzy:
Fromhold, T. M.
Bujkiewicz, S.
Patanè, A.
Stapleton, S. P.
Sherwood, D.
Fowler, D.
Cooper, J.
Eaves, L.
Belyaev, A. E.
Krokhin, A. A.
Neumann, A.
Wilkinson, P. B.
Sankeshwar, N. S.
Henini, M.
Sheard, F. W.
Powiązania:
https://bibliotekanauki.pl/articles/2044604.pdf
Data publikacji:
2006-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.At
73.21.Cd
Opis:
We explore a new regime of hot carrier dynamics, in which electrons in a superlattice miniband exhibit a unique type of stochastic motion when a magnetic field is tilted at an angle θ to the superlattice axis. Remarkably, the dynamics of a miniband electron in a tilted magnetic field reduce to a one-dimensional simple harmonic oscillator, of angular frequency ω$\text{}_{C}$ cos θ, where ω$\text{}_{C}$ is the cyclotron frequency, driven by a time-dependent plane wave whose angular frequency equals the Bloch frequency ω$\text{}_{B}$. At bias voltages for which ω$\text{}_{B}$=nω$\text{}_{C}$ cos θ, where n is an integer, the electron orbits change from localised Bloch-like trajectories to unbounded stochastic orbits, which diffuse rapidly through intricate web patterns in phase space. To quantify how these webs affect electron transport, we make drift-diffusion calculations of the current-voltage curves including the effects of space-charge build up. When the magnetic field is tilted, our simulations reveal a large resonant peak, which originates from stochastic delocalisation of the electron orbits. We show that the corresponding quantised eigenstates change discontinuously from a highly localised character when the system is off resonance to a fully delocalised form when the resonance condition is satisfied.
Źródło:
Acta Physica Polonica A; 2006, 109, 1; 43-52
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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