Observation of Dirac Node Formation and Mass Acquisition in a Topological Crystalline Insulator
Observation of Dirac Node Formation and Mass Acquisition in a Topological Crystalline Insulator
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DOI：
10.1126/science.1239451
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发表时间：
2013-09-27
期刊：
影响因子：
56.9
通讯作者：
Madhavan, Vidya
中科院分区：
文献类型：
--
作者：
Okada, Yoshinori;Serbyn, Maksym;Madhavan, Vidya
在拓扑晶体绝缘体（TCI）中，拓扑结构和晶体对称性相互交织，产生具有不同特征的表面态。晶体对称性的破坏在TCI预计给予质量的狄拉克费米子的质量。在这里，我们报告的高分辨率扫描隧道显微镜研究的TCI，Pb 1-xSnxSe，揭示了共存的零质量狄拉克费米子的晶体对称性保护与大量狄拉克费米子符合晶体对称性破缺。此外，我们显示了两个不同的制度的费米表面拓扑分离的Van霍夫奇点在Lifshitz过渡点。我们的工作为在TCI中实现Dirac带隙和相互作用驱动的拓扑量子现象铺平了道路。
In topological crystalline insulators (TCIs), topology and crystal symmetry intertwine to create surface states with distinct characteristics. The breaking of crystal symmetry in TCIs is predicted to impart mass to the massless Dirac fermions. Here, we report high-resolution scanning tunneling microscopy studies of a TCI, Pb1-xSnxSe that reveal the coexistence of zero-mass Dirac fermions protected by crystal symmetry with massive Dirac fermions consistent with crystal symmetry breaking. In addition, we show two distinct regimes of the Fermi surface topology separated by a Van-Hove singularity at the Lifshitz transition point. Our work paves the way for engineering the Dirac band gap and realizing interaction-driven topological quantum phenomena in TCIs.