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Magnetic effects in Mn‐doped CdSe nanocrystals
Author(s) -
Proshchenko Vitaly,
Dahnovsky Yuri
Publication year - 2015
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201552246
Subject(s) - antiferromagnetism , ferromagnetism , ab initio , condensed matter physics , quantum dot , ab initio quantum chemistry methods , exchange interaction , doping , ground state , nanocrystal , materials science , chemistry , molecular physics , atomic physics , physics , molecule , nanotechnology , quantum mechanics
Abstract The concentration dependence of magnetic order of Mn‐doped CdSe nanocrystals is studied. The distance between two Mn atoms imitates the concentration dependence. To do more accurate calculations, we cut three fragments out of a quantum dot and calculate the magnetic order of the ground state. We find that the DFT calculations provide unreliable results where the magnetic order depends on a chosen exchange correlation functional. Then, a more accurate ab initio CASSCF method is applied with a multideterminant basis set. The obtained results indicate the strong sp–d hybridization with the magnetic order oscillations depending on the distance between the Mn atoms. At small and intermediate distances between the Mn atoms, we see a ferromagnetic order, while at larger distances it is antiferromagnetic. Such a dependence can be fitted by the RKKY formula where the parameters for the sp–d exchange constant and k F are found from the fitting procedure.