G. Karczewski

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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)
We present zero-, one-, and two-quantum two-dimensional coherent spectra of excitons and trions in a CdTe/(Cd,Mg)Te quantum well. The set of spectra provides a unique and comprehensive picture of the coherent nonlinear optical response. Distinct peaks in the spectra are manifestations of exciton-exciton and exciton-trion coherent coupling. Excellent(More)
We report on the growth and high spatial resolution magneto-photoluminescence of CdMnTe quantum dots embedded in a ZnCdTe matrix with Mn content of about 3%. The giant Zeeman spitting of excitonic emission coming from individual quantum dots and magnetization fluctuations inside them are studied in magnetic fields up to 7 T. We have found that the(More)
OBJECTIVE Evaluation of multiplex PCR utility for diagnosis of central nervous system disorders in HIV-infected patients. METHODS Multiplex PCR assay for simultaneous detection of HSV-1, HSV-2, VZV, HHV-6, CMV, EBV, JCV, T. gondii DNA in 27 CSF samples from HIV-infected patients was used. PCR results were compared with clinical diagnosis and(More)
By means of spin- and angle-resolved photoelectron spectroscopy we studied the spin structure of thin films of the topological insulator Bi2Se3 grown on InP(111). For thicknesses below six quintuple layers the spin-polarized metallic topological surface states interact with each other via quantum tunneling and a gap opens. Our measurements show that the(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)
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)
We have studied the low energy spin excitations in n-type CdMnTe based dilute magnetic semiconductor quantum wells. For magnetic fields for which the energies for the excitation of free carriers and Mn spins are almost identical, an anomalously large Knight shift is observed. Our findings suggest the existence of a magnetic-field-induced ferromagnetic order(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)