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Wyszukujesz frazę "Furdyna, J." wg kryterium: Autor


Tytuł:
Exciton Binding Energy in Extremely Shallow Quantum Wells
Autorzy:
Kossut, J.
Furdyna, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/1877012.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
71.36.+c
73.61.Ga
Opis:
The usual approach to the problem of excitons in semiconductor quantum wells is to assume that both the electron or the hole are primarily localized in the potential well regions defined by the band offsets, i.e., that the quantum wells are deep. We re-examine the problem of the exciton in the presence of a very shallow square well potential due to the (small) conduction and valence band offsets in a semiconducting heterostructure. We show that the combined effects of the shallow well and the Coulomb interaction between the electron and the hole are equivalent to an effective potential acting on the center-of-mass of a three-dimensional exciton. We calculate the shape of such a potential and show it to be satisfactorily approximated by the potential of a parabolic well.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 528-532
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Phase Diagram of Zinc-Blende Cd$\text{}_{1-x}$Mn$\text{}_{x}$Se
Autorzy:
Sawicki, M.
Furdyna, J. K.
Luo, H.
Powiązania:
https://bibliotekanauki.pl/articles/1952079.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
75.50.Rr
75.50.Lk
Opis:
The paper reports first magnetic measurements performed on MBE grown epilayers of zinc-blende Cd$\text{}_{1-x}$Mn$\text{}_{x}$Se. For all samples studied in the concentration range 0.24 < x < 0.63 we find at low temperatures a history-dependent magnetic response, suggesting a transition to a spin-glass-like state. The central result of the paper is the presentation of a new, complete magnetic phase diagram for this material.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 923-926
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Properties of Diluted Magnetic Semiconductor Quantum Structures
Autorzy:
Dobrowolska, M.
Luo, H.
Furdyna, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/1931886.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Et
73.20.Dx
68.55.Bd
78.20.Ls
Opis:
Conduction and valence band edges in diluted magnetic semiconductors undergo enormous Zeeman shifts when a magnetic field is applied, reaching values in excess of 100 meV at low temperatures. These Zeeman shifts can thus have profound consequences on the properties of DMS/non-DMS heterostructures, since they provide the opportunity of tuning their band alignment by varying an applied field. This leads to a variety of entirely new effects, and also provides a powerful tool for probing the effect of band alignment on the properties of semiconductor heterostructures in general. We illustrate this with several examples. First, using the ZnSe/ZnMnSe system, we discuss the creation of a spatial spin modulation (spin superlattice). Second, we use the drastic differences in the Zeeman splitting occurring in different layers of a DMS/non-DMS superlattice in order to pinpoint the localization in space of the specific electronic states involved in optical transitions. We illustrate this by investigating the localization of above-barrier states in type-I ZnSe/ZnMnSe superlattices, and of spatially-direct (type-I) excitons which occur in ZnTe/CdMnSe and ZnMnTe/CdSe type-II super-lattices. Finally, we exploit Zeeman tuning to demonstrate the confinement effects which occur in a single quantum barrier.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 95-106
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Photomemory Effect in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$:In for Direct Measurements of Magnetization of Bound Magnetic Polarons
Autorzy:
Wojtowicz, T.
Koleśnik, S.
Miotkowski, I.
Furdyna, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/1921550.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.38.+i
75.50.Pp
Opis:
The first direct measurement of the magnetization of donor bound magnetic polarons in diluted magnetic semiconductors is reported. The experiment has been performed taking advantage of photomemory effect found in n-type Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ crystals doped with In. Good agreement between experimental results and theory of bound magnetic polarons is observed.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 637-640
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymmetric Magnetization Reversal in the Exchange-Biased MnO/(Ga,Mn)As Heterostructure Studied by Ferromagnetic Resonance
Autorzy:
Dziatkowski, K.
Ge, Z.
Liu, X.
Furdyna, J. K.
Twardowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2046987.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.30.Gw
75.70.Cn
Opis:
We report ferromagnetic resonance study of the magnetization reversal in the exchange-coupled MnO/(Ga,Mn)As system. The low-field parts of ferromagnetic resonance spectra measured along [1/10] and [100] directions of (Ga,Mn)As were combined into hysteresis loops, which under field-cooling conditions similarly to SQUID loops are shifted toward negative magnetic fields. The magnetization reversal process revealed by the loops occurred remarkably asymmetric for both sample configurations.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 319-324
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiconductor Superlattices with Small Band Offsets - feature article
Autorzy:
Yang, G.
Lewandowski, L. A.
Furdyna, J. K.
Ram-Mohan, L. R.
Powiązania:
https://bibliotekanauki.pl/articles/1968871.pdf
Data publikacji:
1998-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
Opis:
Optical transitions in small band offset superlattices are studied within the framework of the nearly free electron approximation, in which the weak superlattice potential is treated as a perturbation. Interband selection rules are derived for transitions involving conduction and valence band states at the superlattice Brillouin zone center and the zone edge. It is found that a number of new transitions can occur in such small-offset superlattices due to wave function mixing of different subband states. The effect of the effective mass on the optical transitions is also discussed. The theory is used to explain the results observed in magneto-optical absorption experiment in ZnSe/Zn$\text{}_{1-x}$Mn$\text{}_{x}$Se small-offset superlattices. Furthermore, the nearly free electron formulation is found to be in excellent agreement with rigorous multi-band numerical calculation on superlattices involving small band offsets.
Źródło:
Acta Physica Polonica A; 1998, 93, 4; 567-600
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Static and Dynamic Spin Organization in Magnetic Semiconductor Nanostructures
Autorzy:
Samarth, N.
Luo, H.
Furdyna, J. K.
Giebultowicz, T. M.
Awschalom, D. D.
Powiązania:
https://bibliotekanauki.pl/articles/1920966.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.25.+z
Opis:
We describe experiments which study static and dynamic aspects of Mn spin organization in magnetic semiconductor superlattices and quantum wells. Neutron diffraction studies of ZnSe/MnSe and ZnTe/MnSe superlattices show how static Mn spin organization in these antiferromagnetic layers may be modified by strain and lowered dimensionality. We also use a novel form of femtosecond magnetic spectroscopy to examine magnetic polaron dynamics in diluted magnetic semiconductor quantum wells, and show how the organization of Mn spins by a spin-polarized carrier population may be directly viewed in the time domain.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 573-584
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence of Donor-Doped ZnSe Films Grown by Molecular Beam Epitaxy
Autorzy:
Karczewski, G.
Hu, B.
Yin, A.
Luo, H.
Dobrowolska, M.
Furdyna, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/1932090.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Ln
78.55.Et
Opis:
We studied the effect of the donor doping of ZnSe films on their photoluminescence properties. The samples were doped during the molecular beam epitaxy growth, either with gallium or with chlorine. As the dopant concentration dose increases, the intensity of the band-edge emission first saturates, and then quenches in favor of the deep-level photoluminescence band. The main effect of donor doping on photoluminescence is a strong increase in intensity of the donor-bound exciton line, referred to as I$\text{}_{2}$. For Ga-doped films deep-band emission is much stronger, and the I$\text{}_{2}$-line is slightly weaker than for Cl-doped films with comparable doping level. The results confirm the superiority of chlorine over gallium as an n-type dopant in ZnSe. We discuss the photoluminescence results and relate them to deep level transient spectroscopy data obtained on the same samples.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 245-248
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Persistent Spin Resonance of Donor Electrons and Hopping Magnetoconductivity in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$
Autorzy:
Wojtowicz, T.
Semaltianos, N.
Kłosowski, P.
Dobrowolska, M.
Furdyna, J. K.
Miotkowski, I.
Powiązania:
https://bibliotekanauki.pl/articles/1890647.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ls
71.25.Jd
72.20.My
Opis:
The first observation of electric dipole spin resonance of donor electrons in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{y}$ in far-infrared magnetotransmission is reported. Modification of the donor wave function due to non-diagonal exchange interaction with localized magnetic moments and to magnetic fluctuations are believed to allow this resonance. Hopping magnetoconductivity studied in the same crystals shows a behavior typical for wide gap diluted magnetic semiconductors.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 287-290
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetic Resonance Study of Exchange Coupled (Ga,Mn)As/GaAs/(Ga,Mn)As Heterostructures
Autorzy:
Dziatkowski, K.
Ge, Z.
Liu, X.
Furdyna, J. K.
Clerjaud, B.
Twardowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047381.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.50.+g
75.70.Cn
75.30.Et
85.75.-d
Opis:
Ferromagnetic resonance study of the exchange coupled (Ga,Mn)As/ GaAs/(Ga,Mn)As heterostructures is reported. The measurements were performed on the series of samples with varying thicknesses d$\text{}_{GaAs}$ of nonmagnetic GaAs spacer, established d$\text{}_{GaAs}$-dependent extent of weak and strong interlayer exchange coupling, judging on the observation of one or two ferromagnetic resonance modes.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 227-232
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Growth Break before Capping on Photoluminescence Dynamics of CdSe/ZnSe Self-Assembled Quantum Dots
Autorzy:
Nowak, S.
Suffczyński, J.
Goryca, M.
Kossacki, P.
Gaj, J.
Lee, S.
Furdyna, J.
Powiązania:
https://bibliotekanauki.pl/articles/1811967.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.67.Hc
81.07.Ta
Opis:
Influence of growth breaks before capping of CdSe self-assembled quantum dot layers on photoluminescence dynamics was examined in three samples. Short (5s) break resulted only in a small blue shift, caused probably by partial strain relaxation and/or Zn interdiffusion. Long (20 min) break induced a strong broadening and red shift of the spectra, combined with a dramatic slow down of the photoluminescence decays. The main result of the long break was identified as introduction of defects (impurities), which generate local electric fields and act as traps of photogenerated carriers.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1267-1271
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Coupling in Magnetic Semiconductor Multilayers and Superlattices
Autorzy:
Furdyna, J.
Leiner, J.
Liu, X.
Dobrowolska, M.
Lee, S.
Chung, J.
Kirby, B.
Powiązania:
https://bibliotekanauki.pl/articles/1426668.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
61.05.fj
75.47.De
75.70.Cn
Opis:
The study of ferromagnetic semiconductors continues to be of great interest because of their potential for spintronic devices. While there has been much progress in our understanding of ferromagnetic semiconductor materials - particularly of the canonical III-V system $Ga_{1-x}Mn_xAs$ - many issues still remain unresolved. One of these is the nature of interlayer exchange coupling in GaMnAs-based multilayers, an issue that is important from the point of view of possible spintronic applications. In this connection, it is important to establish under what conditions the interlayer exchange coupling between successive GaMnAs layers is antiferromagnetic or ferromagnetic, since manipulation of such interlayer exchange coupling can then be directly applied to achieve giant magnetoresistance and other devices based on this material. In this review we will describe magneto-transport, magnetization, and neutron reflectometry experiments applied to two types of GaMnAs-based multilayer structures - superlattices and tri-layers - consisting of GaMnAs layers separated by non-magnetic GaAs spacers. These measurements serve to identify conditions under which AFM coupling will occur in such GaMnAs/GaAs multilayer systems, thus providing us the information which can be used for manipulating magnetization (and thus also giant magnetoresistance) in structures based on the ferromagnetic semiconductor GaMnAs.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 973-980
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Strain in II-VI Semiconductor Superlattices Using Electron Paramagnetic Resonance of Mn$\text{}^{++}$
Autorzy:
Furdyna, J. K.
Qazzaz, M.
Yang, G.
Montes, L.
Xin, S. H.
Luo, H.
Powiązania:
https://bibliotekanauki.pl/articles/1933687.pdf
Data publikacji:
1995-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
71.55.Gs
Opis:
We explore the possibility of using electron paramagnetic resonance (EPR) of Mn$\text{}^{++}$ for measuring uniaxial strain in II-VI superlattices. This work is motivated by the fact that the EPR spectrum of Mn$\text{}^{++}$ is very strongly affected by crystalline fields. Changes in a crystalline field which arise from strain are thus automatically expected to have a profound effect on the EPR spectrum. Consistent with this expectation, we have observed giant crystal field splittings of Mn$\text{}^{++}$ EPR lines in ZnTe/MnTe, CdTe/MnTe, and ZnTe/MnSe superlattices. The EPR spectra observed in these systems are ascribed to isolated Mn$\text{}^{++}$ ions diffused into the ZnTe or the CdTe layers from the respective MnTe or MnSe layers. In addition to providing precise information oii the magnitude and the sign of strain produced by lattice mismatch between the superlattice constituents, we show that the EPR spectrum also provides a direct measure of strain fluctuations in the layered medium.
Źródło:
Acta Physica Polonica A; 1995, 88, 4; 607-618
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Far-Infrared Magneto-Optical Studies of HgTe-CdTe Superlattices in the Semimetallic Regime
Autorzy:
Wojtowicz, T.
Dobrowolska, M.
Furdyna, J.K.
Meyer, J. R.
Bartoli, F. J.
Hoffman, C. A.
Ram-Mohan, L. R.
Powiązania:
https://bibliotekanauki.pl/articles/1888086.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.65.Fa
78.30.Fs
Opis:
We review recent magneto-optical investigations performed on HgTe-CdTe semimetallic superlattices. Far infrared magnetotransmission data obtained as a function of temperature, photon energy, and sense of circular polarization are compared with the predictions of a comprehensive new theory which fully incorporates the complexities of type-III superlattice band structure. It is found that the theory accounts for nearly all of the many unusual features which have been observed experimentally. These include the occurrence of two cyclotron resonances due to holes; the coexistence of electron and hole cyclotron resonances in the low temperature limit; the observation of three distinct CRA minima; a step-like change in the temperature dependence of the electron cyclotron mass; and a dramatic increase of the CRI absorption peak intensity with increasing magnetic field.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 245-254
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnons in Cubic MBE-Grown A$\text{}_{1-x}$Mn$\text{}_{x}$Te Layers (A = Cd, Zn, Mg)
Autorzy:
Szuszkiewicz, W.
Hennion, B.
Jouanne, M.
Morhange, J. F.
Dynowska, E.
Janik, E.
Wojtowicz, T.
Zieliński, M.
Furdyna, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/1992341.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.12.-q
75.50.Pp
78.30.-j
Opis:
One-magnon excitations in MBE-grown A$\text{}_{1-x}$Mn$\text{}_{x}$Te layers (where A = Cd, Zn, Mg and x>0.7) were investigated by means of the Raman scattering measurements at low temperatures (≈20 K). The composition dependence of the anisotropy energy - as extracted from these measurements - is discussed. Further, the elastic neutron scattering measurements were performed in layers of cubic MnTe, which constitute the end point material of the ternary alloys series. Abundance of variously oriented antiferromagnetic domains in MnTe layers as a function of temperature was studied. We confirm occurrence of a pronounced magnetostriction effect.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 583-587
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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