Single crystalline nanostructures of topological crystalline insulator SnTe with distinct facets and morphologies.
Single crystalline nanostructures of topological crystalline insulator SnTe with distinct facets and morphologies.
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DOI：
10.1021/nl4030193
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发表时间：
2013-01-01
期刊：
影响因子：
10.8
通讯作者：
Zhang, S X
中科院分区：
文献类型：
--
作者：
Li, Z;Shao, S;Zhang, S X
拓扑晶体绝缘体（TCI）是一类新型拓扑材料，具有独特的金属表面状态的晶体镜像对称保护。它们的拓扑表面性质预计强烈依赖于表面取向。通过结合密度泛函理论（DFT）计算和合成实验，我们证明了控制生长的单晶纳米结构的原型TCI SnTe具有不同的方面和形态。我们的计算表明，{111}表面的过剩能量可以高于或低于{100}表面的过剩能量，这取决于化学计量比，而{110}总是高于{100}。在我们的合成实验中，我们通过调整生长温度来定性地控制化学计量比，得到了两种类型的单晶纳米线：在高温下由{100}面主导的光滑纳米线和在低温下由{100}和{111}面组成的锯齿形纳米线。值得注意的是，在我们的纳米结构中没有{110}面，这有力地支持了DFT计算。我们的设备制造和电气特性表明，这两种类型的纳米线是适合的拓扑表面态的输运研究。
Topological crystalline insulators (TCIs) are a new class of topological materials that possess unique metallic surface states protected by crystalline mirror symmetry. Their topological surface properties are expected to strongly depend on the surface orientation. By combining density functional theory (DFT) calculations and synthesis experiments, we demonstrate the controlled growth of single crystalline nanostructures of the prototypical TCI SnTe with distinct facets and morphologies. Our calculations suggest that the excess energy of the {111} surfaces can be either higher or lower than that of the {100} surfaces, depending on the stoichiometry, while the {110} is always higher than the {100}. In our synthesis experiment, we qualitatively controlled the stoichiometry by tailoring the growth temperature and obtained two types of single crystalline nanowires: smooth nanowires dominated by {100} facets at high temperatures and zigzag nanowires composed of both {100} and {111} surfaces at low temperatures. Notably, there is no {110} facet in our nanostructures, strongly supporting the DFT calculations. Our device fabrication and electrical characterizations suggest that both types of nanowires are suitable for transport studies of topological surface states.