A stable three-dimensional topological Dirac semimetal Cd3As2
A stable three-dimensional topological Dirac semimetal Cd3As2
复制标题
稳定的三维拓扑狄拉克半金属Cd3As2
DOI：
10.1038/nmat3990
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发表时间：
2014-07-01
期刊：
影响因子：
41.2
通讯作者：
Chen, Y. L.
中科院分区：
文献类型：
--
作者：
Liu, Z. K.;Jiang, J.;Chen, Y. L.
三维拓扑狄拉克半金属是近年来提出的一种量子物质态，在物理学和材料科学中引起了越来越多的关注。3D TDS不仅是石墨烯的块状类似物;它还在其电子结构中表现出与拓扑绝缘体相似的非平凡拓扑结构。此外，TDS可以被驱动到其他奇异相（如Weyl半金属（1，7），轴子绝缘体（1，4）和拓扑超导体（8，9）），使其成为研究这些状态及其之间相变的独特母体化合物。在这里，通过进行角分辨光电子能谱，我们直接观察到一对三维狄拉克费米子在Cd 3As 2，证明它是一个模型的三维TDS。与其他三维TDS相比，如β-方石英BiO 2（参考文献3）和Na 3Bi（参考文献4，5），Cd 3As 2是稳定的，并具有更高的费米速度。此外，通过原位掺杂，我们已经能够调整其费米能量，使其成为探索奇异物理现象的灵活平台。
Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter(1-6) that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals(1,7), axion insulators(1,4) and topological superconductors(8,9)), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd3As2, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, beta-cristobalite BiO2 (ref. 3) and Na3Bi (refs 4,5), Cd3As2 is stable and has much higher Fermi velocities. Furthermore, by in situ doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.