Bergqvist L, Eriksson O, Kudrnovský J, Drchal V, Korzhavyi P, Turek I
Department of Physics, Uppsala University, Box 530, 751 21 Uppsala, Sweden.
Phys Rev Lett. 2004 Sep 24;93(13):137202. doi: 10.1103/PhysRevLett.93.137202.
We demonstrate that the magnetic properties of diluted magnetic semiconductors are dominated by short ranged interatomic exchange interactions that have a strong directional dependence. By combining first principles calculations of interatomic exchange interactions with a classical Heisenberg model and Monte Carlo simulations, we reproduce the observed critical temperatures of a broad range of diluted magnetic semiconductors. We also show that agreement between theory and experiment is obtained only when the magnetic atoms are randomly positioned. This suggests that the ordering of diluted magnetic semiconductors is heavily influenced by magnetic percolation, and that the measured critical temperatures should be very sensitive to details in the sample preparation, in agreement with observations.
我们证明，稀磁半导体的磁性由具有强烈方向依赖性的短程原子间交换相互作用主导。通过将原子间交换相互作用的第一性原理计算与经典海森堡模型及蒙特卡罗模拟相结合，我们再现了多种稀磁半导体观测到的临界温度。我们还表明，只有当磁性原子随机分布时，理论与实验才能达成一致。这表明稀磁半导体的有序化受到磁渗流的严重影响，并且所测得的临界温度应该对样品制备的细节非常敏感，这与观测结果相符。
