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Clustering in disordered ferromagnets: The Curie temperature in diluted magnetic semiconductors

D. J. Priour Jr·S. Das Sarma
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Abstract

We theoretically investigate impurity correlation and magnetic clustering effects on the long-range ferromagnetic ordering in diluted magnetic semiconductors, such as $\textrm{Ga}_{1-x}\textrm{Mn}_{x}\textrm{As}$, using analytical arguments and direct Monte Carlo simulations. We obtain an analytic formula for the ferromagnetic transition temperature $T_{c}$ which becomes asymptotically exact in the strongly disordered, highly dilute (i.e. small $x$) regime. We establish that impurity correlations have only small effects on $T_{c}$ with the neutrally correlated random disorder producing the nominally highest $T_{c}$. We find that the ferromagnetic order is approached from the high temperature paramagnetic side through a random magnetic clustering phenomenon consistent with the percolation transition scenario.

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D. J. Priour Jr, S. Das Sarma. 2006-02-22. Clustering in disordered ferromagnets: The Curie temperature in diluted magnetic semiconductors. https://doi.org/10.1103/physrevb.73.165203

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