Topology-Driven Magnetic Quantum Phase Transition in Topological Insulators
Topology-Driven Magnetic Quantum Phase Transition in Topological Insulators
复制标题
拓扑绝缘体中拓扑驱动的磁量子相变
DOI：
10.1126/science.1230905
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发表时间：
2013-03-29
期刊：
影响因子：
56.9
通讯作者：
Wang, Yayu
中科院分区：
文献类型：
--
作者：
Zhang, Jinsong;Chang, Cui-Zu;Wang, Yayu
在掺杂铬的Bi2(SexTe1-x)3薄膜中可以观察到同时发生的拓扑和磁量子相变，这是由于其能带结构的特殊性，人们可以通过化学掺杂诱导拓扑平凡和非平凡材料之间的转变。现在，J. Zhang等人（p. 1582）更进一步——同时观察到，在分子束外延生长并掺杂磁性Cr的Bi2(SexTe1-x)3薄膜中，Se和Te的比例随磁性量子跃迁而变化。光发射和输运实验以及密度泛函计算表明，拓扑跃迁诱导磁性。拓扑绝缘体中时间反转对称性的破坏可能会产生以前未知的量子效应。我们在分子束外延生长的掺杂cr的Bi2(SexTe1-x)3拓扑绝缘体薄膜中观察到磁量子相变。在临界点上，通过角分辨光发射测量和密度泛函理论计算揭示了拓扑量子相变。我们提供了强有力的证据，证明体带拓扑结构是磁量子相变的基本驱动力。该系统具有可调谐的拓扑和磁性能，非常适合实现磁性拓扑绝缘体中的奇异拓扑量子现象。
Simultaneous topological and magnetic quantum phase transitions are observed in thin films of Bi2(SexTe1-x)3 doped with chromium Topological insulators owe their exotic properties to the peculiarities of their band structure, and one can induce a transition between a topologically trivial and nontrivial material by chemical doping. Now, J. Zhang et al. (p. 1582) have gone a step further—simultaneously observing that a magnetic quantum transition as the ratio of Se and Te is varied in Bi2(SexTe1-x)3 thin films grown by molecular beam epitaxy and doped with magnetic Cr. Photoemission and transport experiments, as well as density functional calculations, imply that the topological transition induces magnetism The breaking of time reversal symmetry in topological insulators may create previously unknown quantum effects. We observed a magnetic quantum phase transition in Cr-doped Bi2(SexTe1-x)3 topological insulator films grown by means of molecular beam epitaxy. Across the critical point, a topological quantum phase transition is revealed through both angle-resolved photoemission measurements and density functional theory calculations. We present strong evidence that the bulk band topology is the fundamental driving force for the magnetic quantum phase transition. The tunable topological and magnetic properties in this system are well suited for realizing the exotic topological quantum phenomena in magnetic topological insulators.