Defect-induced magnetism in II-VI quantum dots

The identification of physical parameters that lead to magnetism in apparent nonmagnetic semiconductor systems has continuously challenged our community. In particular, for quantum-dot systems, they are key factors that contribute to their magneto-optical properties. We report, experimentally, optical evidences of induced nanomagnetism in nonmagnetic CdSe quantum dots and assess theoretically the role played by charged and uncharged vacancies. The analysis of these effects rests upon both the chemical and strain environments where the quantum dots are embedded. The interplay of spin-orbit interaction with built-in axial strains has been demonstrated to be a key factor for the magnetic moment alignment. This has been achieved in this paper by emulating the electronic structure at atomistic levels, considering various defect configurations and taking into account both the quantum dot composition and the influence of the host lattice.