T. Kazimierczuk, T. Smoleński, J. Kobak, M. Goryca, W. Pacuski, A. Golnik, K. Fronc, Łukasz Kłopotowski, P. Wojnar, P. Kossacki
We present an experimental study of electron-electron exchange interaction in self-assembled CdTe/ZnTe quantum dots based on the photoluminescence measurements. The character and strength of this interaction are obtained by simultaneous observation of various recombination channels of a doubly negatively charged exciton, including previously unrecognized emission lines related to the electron-singlet configuration in the final state. A typical value of the electron singlet-triplet splitting, which corresponds to the exchange integral of electron-electron interaction, has been determined as 20.4 meV with a spread of 1.4 meV across the wide population of quantum dots. We also evidence an unexpected decrease of energy difference between the singlet and triplet states under a magnetic field in Faraday geometry.
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http://arxiv.org/abs/1304.5914
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