Wojciech Pacuski - Magnetic ground state of an individual Fe2+ ion in strained semiconductor nanostructure

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      Publication Details (including relevant citation   information):

      T. Smoleński, T. Kazimierczuk, J. Kobak, M. Goryca, A.   Golnik, P. Kossacki, W. Pacuski, Nature Communications 7, 10484   (2016).


      Single impurities with nonzero spin and multiple ground states   offer a degree of freedom that can be utilized to store the   quantum information. However, Fe2+ dopant is known for having a single   nondegenerate ground state in the bulk host semiconductors and   thus is of little use for spintronic applications. Here we show   that the well-established picture of Fe2+ spin configuration can be modified by   subjecting the Fe2+ ion to   high strain, for example, produced by lattice mismatched   epitaxial nanostructures. Our analysis reveals that high strain   induces qualitative change in the ion energy spectrum and results   in nearly doubly degenerate ground state with spin projection   Sz=±2. We   provide an experimental proof of this concept using a new system:   a strained epitaxial quantum dot containing individual   Fe2+ ion. Magnetic character   of the Fe2+ ground state in a   CdSe/ZnSe dot is revealed in photoluminescence experiments by   exploiting a coupling between a confined exciton and the   single-iron impurity. We also demonstrate that the   Fe2+ spin can be oriented by   spin-polarized excitons, which opens a possibility of using it as   an optically controllable two-level system free of nuclear spin   fluctuations.

      Address (URL): http://www.nature.com/ncomms/2016/160128/ncomms10484/full/ncomms10484.html