Temat: 76.40.+b - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Time-Resolved Microwave Spectroscopy of High Electron Mobility GaAs/AlGaAs Structures
Autorzy:: Khachepuridze, A.
Ivanov, V. Yu.
Godlewski, M.
Regiński, K.
Bugajski, M.
Tematy:: 73.20.Dx
76.40.+b
76.70.Hb; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1991552.pdf Link otwiera się w nowym oknie
Opis:: Mechanism of the optical detection of cyclotron resonance via emission from 2D electron gas in modulation doped quantum wells and in high electron mobility structures of GaAs/AlGaAs is discussed based on the results of time-resolved optical detection of cyclotron resonance. An important role of impact ionization processes is demonstrated. We also show that microwave radiation destroys emission enhancement at the Fermi level and the relevant mechanism is proposed.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 2.

Tytuł:: Detection of Single Submillimeter-Wave Photons Using Quantum Dots
Autorzy:: Komiyama, S.
Astafiev, O.
Antonov, V.
Kutsuwa, T.
Tematy:: 73.40.Hm
76.40.+b
72.20.Ht; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2014189.pdf Link otwiera się w nowym oknie
Opis:: Single-photon detection in a range of submillimeter waves (λ = 0.17-0.20 mm) is demonstrated by using lateral semiconductor quantum dots fabricated on a high-mobility GaAs/AlGaAs single heterostructure crystal. When a submillimeter photon is absorbed by the quantum dot while it is operated as a single-electron transistor, it switches on (or off) the conductance through the quantum dot. An incident flux of 0.1 photons/s on an effective detector area, (0.1 mm)$\text{}^{2}$, is detected with a 1 ms time resolution. The effective noise equivalent power is roughly estimated to reach on the order of 10$\text{}^{-22}$ W/Hz$\text{}^{1}\text{}^{/}\text{}^{2}$ , a value superior to the ever reported best values of conventional detectors by a factor more than 10$\text{}^{4}$.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 3.

Tytuł:: Cyclotron Frequencies and Quanta of the Landau Levels in Semiconductors Having Ellipsoidal Fermi Surfaces Studied in Dependence on Direction of the Magnetic Field
Autorzy:: Olszewski, S.
Roliński, T.
Tematy:: 71.70.Di
76.40.+b; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1377818.pdf Link otwiera się w nowym oknie
Opis:: A method of calculating the Landau levels in crystals having the ellipsoidal Fermi surfaces has been presented with an accent put on the directional dependence of the energy quanta defined by the levels. Physically the problem concerns mainly semiconductors examined in a nearly-free electron approximation. In this case the shape of the Fermi surface is defined by three different effective masses entering the electron Hamiltonian. Beyond of the masses the method, which can be applied for an arbitrary direction of the magnetic field, does contain no empirical parameters in its framework.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Optical Detection of Cyclotron Resonance in Serpentine Superlattice Quantum-Wire Arrays
Autorzy:: Świątek, K.
Weman, H.
Miller, M. S.
Petroff, P. M.
Merz, J. L.
Tematy:: 78.66.Fd
76.40.+b
71.25.Jd; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1929679.pdf Link otwiera się w nowym oknie
Opis:: We report low-temperature studies of microwave-induced cyclotron resonance of photo-generated carriers in (Al,Ga)As serpentine superlattice quantum-wire arrays. The geometric size of the parabolic-crescent cross-section of the quantum wires was of the order of 100 Å × 50 Å, depending on the angle of the vicinal substrate and the amount of parabolic curvature. Comparing the obtained spectra, we estimate the relative degree of carrier confinement in the ordered AlGaAs structure.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 5.

Tytuł:: Simple Method for Calculating the Weak-Field Electron Diamagnetism in Cubic Lattices
Autorzy:: Olszewski, S.
Tematy:: 75.20.-g
75.20.En
76.40.+b; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2030424.pdf Link otwiera się w nowym oknie
Opis:: The idea of electron wave packets moving along closed anisotropic Fermi surfaces placed in a constant magnetic field has been applied to the calculation of the orbital magnetic moment of an individual free electron and tightly-bound s-electron in a crystal lattice. In each case the magnetic moment is obtained as a derivative of the electron energy done with respect to the strength of the magnetic field. In the next step, calculations have been extended to electron ensembles. For a free-electron ensemble a thorough calculation of the weak-field magnetic moment gives a result similar to that obtained by a well-known method developed by Landau. On the other hand, calculations done for the s-band of the tightly-bound electrons of metallic iron give an absolute value of the magnetic moment much smaller than in the free-electron case. Simultaneously, the sign of the moment is changed indicating a lowering of the iron band electron energy with magnetization.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 6.

Tytuł:: Magnetotransport and Magnetooptics of InAs$\text{}_{1-x}$Sb$\text{}_{x}$ and Heterojunctions Combinations Formed Between InAs and GaSb, AlSb Or InAs$\text{}_{1 -x}$Sb$\text{}_{x}$
Autorzy:: Stradling, R. A.
Tematy:: 72.20.My
76.40.+b
78.20.Ls; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1968244.pdf Link otwiera się w nowym oknie
Opis:: Cyclotron resonance and interband measurements are reported in magnetic fields up to 160 T for InAs/InAs$\text{}_{1-x}$Sb$\text{}_{x}$ superlattices, one of which is a "self-organised" or "natural" superlattice, and InAs$\text{}_{1-x}$Sb$\text{}_{x}$ epilayers. The samples were grown by MBE at temperatures between 370°C to 500°C. No dependence of the band gap, effective masses or g-values on the growth temperature was detected. Anomalous tilt behaviour was observed for the superlattices. Inversion asymmetry induced spin-splitting of the subbands in gated InAs quantum wells is investigated by means of the Shubnikov-de Haas effect and cyclotron resonance. The non-parabolicity was well fitted by Kane theory, although the measured values of effective mass were substantially higher than predictions. Infrared life time measurements at wavelengths between 6 and 85 microns are undertaken with free electron lasers on InAs/InAs$\text{}_{1-x}$Sb$\text{}_{x}$ superlattices and InAs/AlSb quantum wells. Suppression of the Auger recombination times is demonstrated with the superlattices.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 7.

Tytuł:: Simulations of Noise-Free Stochastic Resonance in Spin-Wave Chaos
Autorzy:: Krawiecki, A.
Reibold, E.
Benner, H.
Sukiennicki, A.
Tematy:: 76.50.+g
75.30.Ds
05.45.+b
05.40.+j; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2013991.pdf Link otwiera się w nowym oknie
Opis:: Numerical simulations of noise-free stochastic resonance and aperiodic stochastic resonance in chaotic ferromagnetic resonance are presented. The model, based on three-magnon interactions between the externally excited uniform mode and pairs of spin waves, shows on-off intermittency. The rf magnetic field amplitude is slowly modulated by a small periodic or aperiodic signal, and the output signal, which reflects the occurrence of laminar phases and bursts in the time series of spin-wave amplitudes, is analyzed. On variation of the dc magnetic field the signal-to-noise ratio of the output signal and the correlation function between modulation and output signal pass a maximum, which indicates the occurrence of periodic and aperiodic stochastic resonance, respectively. The role of thermal magnon excitations in the occurrence of this maximum is clarified. The results are compared with experimental findings obtained in other types of intermittency.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 8.

Tytuł:: NdFeB Permanent Magnets with Various Nd Content
Autorzy:: Žák, T.
Talijan, N.
Ćosović, V.
Grujić, A.
Tematy:: 61.05.cp
76.80.+y
75.50.-y
81.07.-b
81.40.Rs; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1813649.pdf Link otwiera się w nowym oknie
Opis:: Three kinds of commercial Nd-Fe-B based materials were compared using $\text{}^{57}Fe$ Mössbauer spectroscopy and X-ray analysis: near the $Nd_2Fe_{14}B$ stoichiometry and with both lowered and raised Nd content. Magnetically hard $Nd_2Fe_{14}B$ is present in all three materials. In the Nd-low material it is accompanied with the magnetically soft $Fe_3B$ phase, building the nanocomposite structure. In the Nd-rich sample the overstoichiometric Nd atoms seem to build separate phase of Fe-Nd solid solution. None of the materials contain significant content of phases degrading magnetic characteristics, with except of minor $Nd_{1.1}Fe_4B_4$ one.
Dostawca treści:: Biblioteka Nauki

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