在磁拓绝缘体中量子化异常霍尔效应.
Rui Yu1, Wei Zhang, Hai-Jun Zhang
1Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Science (New York, N.Y.)
|June 5, 2010
概括
研究人员预测,用过渡金属合四二胺半导体可以创建磁绝缘体. 这些材料表现出量子异常的霍尔效应,在没有外部磁场的情况下显示量子化的霍尔导电性.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学是一种材料科学.
- 拓学材料 拓学材料
背景情况:
- 异常的霍尔效应是由旋转轨道合驱动的固体中的一个关键的运输现象.
- 量子异常的霍尔绝缘器由于其独特的电子结构,在没有外部磁场的情况下表现出量子化的霍尔效应.
- 传统的稀释磁性半导体需要磁性合的自由载体.
研究的目的:
- 为了预测新的磁拓绝缘体.
- 为了研究四二胺半导体实现量子异常霍尔效应的潜力.
- 探索在拓材料中磁性排序的替代机制.
主要方法:
- 用第一原则计算来研究材料特性.
- 这项研究的重点是与过渡金属 (Cr,Fe) 合的四胺半导体 (Bi2Te3,Bi2Se3,Sb2Te3).
- 进行了电子结构和磁性排序在二维薄膜中的分析.
主要成果:
- 预测合Bi2Te3,Bi2Se3和Sb2Te3形成磁性排序的绝缘体.
- 证明了这些薄膜中的磁顺序导致具有有限的切尔恩数的拓电子结构.
- 观察到霍尔导电量以e2/h的单位量化,这是量子异常霍尔效应的特征.
结论:
- 过渡金属兴奋剂提供了一种途径,以实现四二半导体中的磁性秩序,创造内在的磁性拓绝缘体.
- 这些材料在没有外部磁场的情况下表现出量子异常的霍尔效应,由自发磁矩和自旋轨道合驱动.
- 这些发现为开发基于拓现象的新型自旋电子和量子计算设备开辟了道路.
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