G. Karczewski

Learn More
We report on the observation of the Ising quantum Hall ferromagnet with Curie temperature T(C) as high as 2 K in a modulation-doped (Cd,Mn)Te heterostructure. In this system field-induced crossing of Landau levels occurs due to the giant spin-splitting effect. Magnetoresistance data, collected over a wide range of temperatures, magnetic fields, tilt angles,(More)
Two coupled CdTe quantum dots, selected from a self-assembled system, one of them containing a single Mn ion, were studied by continuous wave and modulated photoluminescence, photoluminescence excitation, and photon correlation experiments. Optical writing of information on the spin state of the Mn ion has been demonstrated, using the orientation of the Mn(More)
Spin-transistor designs relying on spin-orbit interaction suffer from low signal levels resulting from low spin-injection efficiency and fast spin decay. Here, we present an alternative approach in which spin information is protected by propagating this information adiabatically. We demonstrate the validity of our approach in a cadmium manganese telluride(More)
The evolution of the magnetization in (Cd,Mn)Te quantum wells after a short pulse of magnetic field was determined from the giant Zeeman shift of spectroscopic lines. The dynamics in the absence of a static magnetic field was found to be up to 3 orders of magnitude faster than that at 1 T. Hyperfine interaction and strain are mainly responsible for the fast(More)
Static and time-resolved magneto-optical spectra of the ferromagnetic semiconductor (Ga,Mn)As show that a pulsed photoexcitation with a fluence of 10 microJ/cm(2) is equivalent to the application of an external magnetic field of about 1 mT, which relaxes with a decay time of 30 ps. This relaxation is attributed to the spin relaxation of electrons in the(More)
Combination of ferroelectric layers and semiconductor heterostructures with 2D electron gas may lead to a number of new applications from high-mobility field effect transistors with ferroelectric gates to quantum dots patterned with polarization domains at sub-micron scale. One of the fundamental obstacles impeding implementation of such devices is(More)
  • C. Betthausen, P. Giudici, +9 authors D. Weiss
  • 2014
C. Betthausen,1 P. Giudici,1 A. Iankilevitch,1 C. Preis,1 V. Kolkovsky,2 M. Wiater,2 G. Karczewski,2 B. A. Piot,3 J. Kunc,3 M. Potemski,3 T. Wojtowicz,2 and D. Weiss1 1Department of Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany 2Institute of Physics, Polish Academy of Sciences, 02668 Warsaw, Poland 3Laboratoire(More)
Congenital toxoplasmosis results from the primary infection with Toxoplasma gondii during the pregnancy. The more advanced pregnancy the higher risk of foetus infection, however the symptoms might be mild or the infection can be asymptomatic. However, undiagnosed infection in a new born baby results in further development of the disease in early childhood(More)
Giant magnetic linear dichroism (MLD) is observed in the ferromagnetic semiconductor Ga(0.98)Mn(0.02)As. The contribution to this effect induced by the spontaneous magnetization can be clearly identified by azimuthal dependencies. The spectral dependence of the effect in the range from 1.4 to 2.4 eV shows that the MLD induced by the spontaneous(More)