Browsing by Author "Govorov, A. O."

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Coherent Aharonov-Bohm oscillations in type-II (Zn,Mn)Te/ZnSe quantum dots
(2008-06-01)
Sellers, I. R.
;
Whiteside, V. R.
;
Govorov, A. O.
;
Fan, W. C.
;
Chou, W-C.
The magneto-photoluminescence of type-II (Zn,Mn)Te quantum dots is presented. As a result of the type-II band alignment, Aharonov-Bohm (AB) oscillations in the photoluminescence intensity are evident. In addition, an interesting interplay between the AB effect and the spin polarization in these diluted magnetic semiconductor quantum dots is observed. The intensity of the AB oscillations increases with both magnetic field and the degree of optical polarization, indicating that the suppression of spin fluctuations improves the coherence of the system.
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.