Fundamentals and functionalities of silicene, germanene, and stanene
Fundamentals and functionalities of silicene, germanene, and stanene
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DOI：
10.1393/ncr/i2018-10145-y
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发表时间：
2018-03-01
影响因子：
4.5
通讯作者：
Le Lay, G.
中科院分区：
文献类型：
--
作者：
Ezawa, M.;Salomon, E.;Le Lay, G.
二维拓扑绝缘体是当前凝聚态物理研究的热点。首先从基本观点出发，综述了近年来有关单分子膜电子和拓扑性质的研究进展。接下来，我们描述了他们的实验实现外延生长和他们的实际物理性能。我们首先描述一般狄拉克系统的拓扑性质，然后通过引入自旋和谷自由度将其应用于硅烯。在此基础上，我们对一般蜂窝体系中的拓扑绝缘体进行了分类。我们讨论基于蜂窝系统的拓扑电子学。我们引入了拓扑基尔霍夫定律，这是拓扑边态的守恒定律。提出了一种基于拓扑边态的场效应拓扑晶体管。我们表明，即使在随机分布的杂质的存在下，电导量子化。单层拓扑绝缘体是未来拓扑电子学和自旋谷电子学的关键。实现这种单层Si、Ge和Sn新型人工同素异形体的突出例子是在超高真空下在银（111）表面上原位生长的典型3 × 3重构外延硅烯相。它在2012年的实现先于锗烯的合成，随后是锡烯的合成，分别在Au（111）和Bi2Te3衬底上。在单层外延硅烯和锗烯上进一步生长Si和Ge导致显示狄拉克费米子特性的层状薄膜。令人惊讶的是，Si沉积到Ag（110）模板上产生了大量平行的五硅烯样纳米带，这是一维硅的一种新形式。场效应晶体管已经用单层和多层硅烯沟道制造，清楚地展示了硅烯和此类相关材料在电子学中的潜在应用，这些材料与当前普遍存在的Si基技术直接兼容。最后，诱人的前景进行了概述。
Two-dimensional elemental topological insulators including silicene, germanene and stanene are currently the hottest topics in condensed matter physics. We first review the recent progress on electronic and topological properties of their monolayers from a fundamental viewpoint. Next, we describe their experimental realizations by epitaxial growth and their actual physical properties. We start with the description of the topological nature of generic Dirac systems and then apply it to silicene by introducing the spin and valley degrees of freedom. Based on them, we classify all topological insulators in the general honeycomb system. We discuss topological electronics based on honeycomb systems. We introduce the topological Kirchhoff law, which is a conservation law of topological edge states. A field effect topological transistor is proposed based on the topological edge states. We show that the conductance is quantized even in the presence of random distributed impurities. Monolayer topological insulators will be a key for future topological electronics and spin-valleytronics. The outstanding example of the realization of such monolayer Si, Ge and Sn novel artificial allotropes is the canonical 3 x 3 reconstructed epitaxial silicene phase grown in situ under ultra-high vacuum on the silver (111) surface. Its realization in 2012 has preceded the synthesis of germanene, followed by that of stanene, respectively on Au(111) and Bi2Te3 substrates. Further growth of Si and Ge over monolayer epitaxial silicene and germanene leads to layered thin films displaying Dirac fermion characteristics. Amazingly, Si deposition onto Ag(110) templates yields massively parallel, pentasilicene-like nanoribbons, a novel form of one-dimensional silicon. Field Effect Transistors have been already fabricated both with single and multi-layer silicene channels, clearly demonstrating potential applications in electronics of silicene and such related materials, which are directly compatible with the current, ubiquitous, Si-based technology. Finally, enticing prospects are outlined.