Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

6 Acta Physica Polonica A

Znaleziono wyników: 6

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Characterization of Interfaces in Semimagnetic Quantum Wells

100%

Schmitt G. , Kuhn-Heinrich B. , Zehnder U. , Ossau W. , Litz T. , Waag A. , Landwehr G.

Acta Physica Polonica A

1995

tom 88

nr 5

897-900

The interfaces between nonmagnetic CdTe quantum wells and semimagnetic barriers of Cd_{1-x}Mn_{x}Te were investigated for several well widths by low temperature photoluminescence and photoluminescence excitation spectroscopy. Specially designed Cd_{1-x}Mn_{x}Te/CdTe/Cd_{1-y}Mg_{y}Te structures enable us to distinguish the quality of the semimagnetic normal and inverted interfaces. The normal interface shows to have a better structural quality than the inverted interface.

Dimensional Dependence of Exchange Interactions at High Magnetic Fields

100%

Zehnder U. , Kuhn-Heinrich B. , Ossau W. , Waag A. , Landwehr G. , Cheng H. , Nicholas R.

Acta Physica Polonica A

1996

tom 90

nr 5

989-992

We studied the contribution of the breaking of antiferromagnetically coupled spin clusters to the total magnetization in thin (CdMn)Te layers as a function of the layer thickness by reflectivity spectroscopy in magnetic fields up to 45 T. The experimental results show that the contribution of the breaking of antiferromagnetically coupled spin clusters is reduced by decreasing layer thickness.

Effect of Spin-Glass Phase Formation on Exciton Magnetic Polaron in (Cd,Mn)Te

100%

Chudnovskiy A. L. , Rosenow B. , Oppermann R. , Yakovlev D. , Zehnder U. , Ossau W.

Acta Physica Polonica A

1996

tom 90

nr 4

755-758

The influence of the spin-glass phase formation of the (Cd,Mn)Te semimagnetic layers on properties of the exciton magnetic polaron were investigated both theoretically and experimentally. The theoretical model offers a consistent description of the temperature dependence of the exciton magnetic polaron energy in the vicinity of spin-glass transition and shows good agreement with the experimental data.

Exciton States in Type-II ZnSe/BeTe Quantum Wells

84%

Platonov A. V. , Yakovlev D. R. , Zehnder U. , Kochereshko V. P. , Ossau W. , Fischer F. , Litz T. , Waag A. , Landwehr G.

Acta Physica Polonica A

1997

tom 92

nr 5

953-957

We present an optical investigation of novel heterostructures based on beryllium chalcogenides with a type-I and type-II band alignment. In the type-II quantum well structures (ZnSe/BeTe) we observed a strong exciton transition involving an electron confined in the conduction band well and a hole localized in the valence band barrier (both in ZnSe layer). This transition is drastically broadened by the temperature increase due to enhanced exciton-acoustic phonon interaction.

Investigation of Spin-Glass Transition in Semimagnetic Quantum Wells Based on Cd_{1-x}Mn_{x}Te by Means of Optical Spectroscopy

84%

Zehnder U. , Yakovlev D. R. , Ossau W. , Waag A. , Landwehr G. , Wojtowicz T. , Karczewski G. , Kossut J.

Acta Physica Polonica A

1997

tom 92

nr 5

1075-1078

The spin-glass transition in Cd_{1-x}Mn_{x}Te epitaxial layers and bulk samples with 0.24 ≤ x ≤ 0.43 and in quantum well structures on the basis of Cd_{1-x}Mn_{x}Te were investigated by means of optical spectroscopy. Reduction of dimensionality of Cd_{1-x}Mn_{x}Te layers down to the quasi-two-dimensional case realized in Cd_{1-x}Mn_{x}Te/Cd_{1- y}Mn_{y}Te heterostructures frustrates the spin-glass formation, which is in agreement with theoretical predictions. The spin-glass formation is also frustrated in the vicinity of interfaces between semimagnetic and nonmagnetic semiconductors in CdTe/Cd_{1-x}Mn_{x}Te quantum wells.

Cd_{1-x}Mn_{x}Te Parabolic Quantum Wells

84%

Wojtowicz T. , Kutrowski M. , Cywiński G. , Dynowska E. , Karczewski G. , Kossut J. , Fiederling R. , Mackh G. , Zehnder U. , Ossau W.

Acta Physica Polonica A

1996

tom 90

nr 5

977-980

We report on the growth and optical studies of II-VI semiconductor parabolic quantum wells made of Cd_{1-x}Mn_{x}Te for a broad range of quantum well widths and Mn molar fractions x. Photoluminescence excitation spectra revealed several series of peaks equidistant in energy associated with interband optical transitions between harmonic oscillator levels. From the analysis of the spectra the valence band offset Q_{hh} = 0.44±0.1 was determined for the CdTe/Cd_{1-x}Mn_{x}Te system.