Thin Films of Magnetically Doped Topological Insulator with Carrier-Independent Long-Range Ferromagnetic Order
Thin Films of Magnetically Doped Topological Insulator with Carrier-Independent Long-Range Ferromagnetic Order
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具有载流子无关长程铁磁序的磁掺杂拓扑绝缘体薄膜
DOI：
10.1002/adma.201203493
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发表时间：
2013-02-20
影响因子：
29.4
通讯作者：
Xue, Qi-Kun
中科院分区：
文献类型：
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作者：
Chang, Cui-Zu;Zhang, Jinsong;Xue, Qi-Kun
近年来，拓扑绝缘体作为一类新概念量子材料，无论是凝聚态物理学还是材料科学都对它产生了浓厚的兴趣。[1，2] TI在费米能级处具有带隙的体能带，与通常的绝缘体相同，但在其所有表面处具有无带隙，Diractype和自旋分裂表面态，这些表面态受到时间反演对称性（TRS）的保护。这类特殊的表面态有望表现出各种独特的量子现象，可能会给低功耗电子学和拓扑量子计算带来革命性的发展。[1，2]大部分的量子现象是由于TI的TRS被打破，比如说，在它们中引入铁磁性。[3-6]例如，具有垂直磁各向异性的铁磁TI薄膜，无论是三维（3D）还是二维（2D），都被预测显示出量子霍尔（QH）效应，而不需要外部磁场，非常高的样品质量，甚至低温，因为特殊的QH效应不依赖于明确定义的朗道能级的形成。[3-6]这种容易获得的QH效应，被称为量子化反常霍尔（QAH）效应，已经被追求了几十年，因为它的实现将打开将新颖的QH效应应用到真实的器件中的可能性。[第7-10页]
In recent years, topological insulators (TIs), as a class of new concept quantum materials, have received substantial research interests from not only condensed matter physics but also material science.[1, 2] A TI has its bulk band gapped at Fermi level, the same as usual insulators, but hosts gapless, Diractype, and spin-split surface states at all of its surfaces which are protected by the time reversal symmetry (TRS). The special kind of surface states is expected to exhibit various unique quantum phenomena which may bring revolutionary developments in low power electronics and topological quantum computation.[1, 2] A large portion of the quantum phenomena results from breaking of the TRS of TIs by, say, introducing ferromagnetism in them.[3–6] For example, a thin film of a ferromagnetic TI, no matter three-dimensional (3D) or two-dimensional (2D) one, with perpendicular magnetic anisotropy is predicted to show quantum Hall (QH) effect without needing external magnetic field, very high quality of samples, and even low temperature, because the special QH effect does not depend on the formation of well-defined Landau levels.[3–6] This kind of easy access QH effect, known as quantized anomalous Hall (QAH) effect, has been sought after for decades since its realization would open the possibility of applying the novel QH effect into real devices.[7–10]