利用可调节自旋过滤器模型,计算并讨论了磁场和电子跃迁能量间隔变化对量子点接触结构中自旋电子过滤特性的影响.研究发现,磁场和电子跃迁能量间隔的变化引起了自旋电子隧穿概率和隧穿电导都呈现出量子台阶效应,磁场的增加使电子的回旋频率和Zeeman能级分裂同时加强,从而导致量子点接触结构中的横向约束加强,而自旋过滤效应明显减弱;当磁场一定时,电子跃迁能量间隔越小,电子的自旋过滤效应越明显.电子跃迁能量间隔改变的同时,也改变了鞍形势的势垒形状和自旋过滤的灵敏度.对于不同的材料,同时考虑磁场和电子跃迁能量间隔的作用可以找到自旋过滤器的最佳过滤效果.尤为重要的是过滤器的结构用标准的电子束技术很容易得到,所以研究结论为设计新型自旋过滤器提供了理论依据,具有广阔的应用前景和潜在的商业价值.此外,使用朗道因子值较高的材料作自旋过滤器的衬底,可以进一步提高过滤器的性能.
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