CMP Division, Saha Institute of Nuclear Physics, HBNI, Kolkata, 700064, India.
SKCG Autonomous College, Paralakhemundi, Odisha, 761200, India.
Sci Rep. 2017 Aug 29;7(1):9603. doi: 10.1038/s41598-017-09729-6.
We investigate the magnetic and the transport properties of diluted magnetic semiconductors using a spin-fermion Monte-Carlo method on a simple cubic lattice in the intermediate coupling regime. The ferromagnetic transition temperature T shows an optimization behavior with respect to the absolute carrier density p and the magnetic impurity concentration x as seen in the experiments. Our calculations also show an insulator-metal-insulator transition across the optimum p where the T is maximum. Remarkably, the optimum p values lie in a narrow range around 0.11 (holes/site) for all x values and the ferromagnetic T increases with x. We explain our results using the polaron percolation mechanism and outline a new route to enhance the ferromagnetic transition temperature in experiments.
我们使用简单立方晶格上的自旋-费米蒙特卡罗方法研究了稀磁半导体的磁和输运性质，该方法处于中间耦合状态。正如实验中所看到的，铁磁转变温度 T 表现出与绝对载流子密度 p 和磁性杂质浓度 x 的优化行为。我们的计算还表明，在最佳 p 处存在一个从绝缘到金属再到绝缘的转变，在这个最佳 p 处，T 达到最大值。值得注意的是，对于所有 x 值，最佳 p 值都在 0.11（空穴/位）左右的狭窄范围内，而铁磁 T 随 x 增加而增加。我们使用极化子渗流机制来解释我们的结果，并概述了在实验中提高铁磁转变温度的新途径。
