PUB - Publikationen an der Universität Bielefeld

Inter- and intra-dot structures of an assembly of ferromagnetically coupled quantum dots are analyzed within the randomly jumping interacting moments (RJIM) model including quantum effects due to the dot discrete levels and disorder. At the magnetic jump anomalies due to quantization the magnetic state equation (MSE) and phase diagrams are found to indicate an existence of spinodal regions and critical points. Arrays of dots with multiple magnetic response anomalies are predicted to display some specific features. In a case of weak coupling such arrays exhibit the well-separated instability regions surrounding the anomaly positions. With increase in coupling we observe further structure modification, plausibly, of bifurcation type. At strong coupling the instability region becomes wide while the stable regime arises as a narrow islands at small disorders. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim