Browsing by Author "Eginligil, M."

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Robust Coherent Magneto-optical Properties of Columnar Type-II Quantum Dots in ZnTe/ZnSe and ZnMnTe/ZnSe Systems
(2011-01-01)
Whiteside, V. R.
;
Sellers, I. R.
;
Eginligil, M.
;
Oszwaldowski, R.
;
Petrou, A.
We present recent experimental results that show strong optical AB effects in the magneto-photoluminescence of columnar II-VI quantum dots (QDs). The AB effects manifest themselves as oscillations in the photoluminescence energy and intensity with magnetic field. It will be shown that this coherent behavior is remarkably robust, persisting at 180K. We, also, present results for a magnetic system, ZnMnTe QDs. These magnetic type-II systems also display evidence of robust magnetic ordering. This behavior is attributed to the formation of magnetic polarons caused by the exchange interaction between strongly localized holes and Mn ions within the QDs. Time-resolved PL measurements display evidence of magnetic polarons up to 200K with a binding energy of approximately 40 meV.
Robust magnetic polarons in type-II (Zn, Mn) Te/ZnSe magnetic quantum dots
(2010-11-18)
Sellers, I. R.
;
Oszwaldowski, R.
;
Whiteside, V. R.
;
Eginligil, M.
;
Petrou, A.
We present a magneto-optical study of magnetic polarons in type-II (Zn, Mn) Te quantum dots. The polarons are formed due to the exchange coupling between the spins of the holes and those of the Mn ions, both of which are localized in the dots. In our photoluminescence studies, the magnetic polarons are detected at temperatures up to similar to 150 K, with a formation energy of similar to 40 meV. The emission from these dots exhibits an unusually small Zeeman shift with applied magnetic field (similar to 2 meV at 8 T) and at the same time a very large circular polarization. We attribute this apparently contradictory behavior by a low and weakly temperature-dependent magnetic susceptibility due to antiferromagnetic coupling of the Mn spins.
Robust magnetic polarons in type-II (Zn, Mn) Te/ZnSe magnetic quantum dots
(2010-11-18)
Sellers, I. R.
;
Oszwaldowski, R.
;
Whiteside, V. R.
;
Eginligil, M.
;
Petrou, A.
We present a magneto-optical study of magnetic polarons in type-II (Zn, Mn) Te quantum dots. The polarons are formed due to the exchange coupling between the spins of the holes and those of the Mn ions, both of which are localized in the dots. In our photoluminescence studies, the magnetic polarons are detected at temperatures up to similar to 150 K, with a formation energy of similar to 40 meV. The emission from these dots exhibits an unusually small Zeeman shift with applied magnetic field (similar to 2 meV at 8 T) and at the same time a very large circular polarization. We attribute this apparently contradictory behavior by a low and weakly temperature-dependent magnetic susceptibility due to antiferromagnetic coupling of the Mn spins.