A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases.
A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases.
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一种新型人工凝聚态晶格和一维拓扑相的新平台
DOI：
10.1126/sciadv.1501692
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发表时间：
2017-03
期刊：
影响因子：
13.6
通讯作者：
Hasan MZ
中科院分区：
文献类型：
--
作者：
Belopolski I;Xu SY;Koirala N;Liu C;Bian G;Strocov VN;Chang G;Neupane M;Alidoust N;Sanchez D;Zheng H;Brahlek M;Rogalev V;Kim T;Plumb NC;Chen C;Bertran F;Le Fèvre P;Taleb-Ibrahimi A;Asensio MC;Shi M;Lin H;Hoesch M;Oh S;Hasan MZ
拓扑保护的电子态在真实的空间中人工排列形成高度可调谐的涌现原子链。凝聚态物理学中的工程晶格，如冷原子光学晶格或光子晶体，可以具有与天然存在的电子晶体根本不同的性质。我们报道了一种新型的人工量子物质晶格。我们的晶格是由拓扑绝缘体和普通绝缘体交替薄膜构成的多层异质结构。每个界面内的异质结构主机一组拓扑保护的界面状态，并通过使层足够薄，我们第一次展示了跨层的界面状态的杂交。通过这种方式，我们的异质结构形成了一个新兴的原子链，其中的界面作为晶格位点和界面态作为原子轨道，从我们的角度分辨光电子能谱测量。通过改变异质结构的组成，我们可以直接控制晶格位置之间的跳跃。我们实现了一个拓扑和平凡的阶段，在我们的超晶格能带结构。我们认为，超晶格可以通过一维拓扑不变量来表征，该不变量与Su-Schrieffer-Heeger模型的不变量密切相关。我们的拓扑绝缘体异质结构展示了一种新颖的实验平台，在该平台上，我们可以通过直接控制电子如何在晶格位置之间跳跃来设计能带结构。
Topologically protected electron states arranged artificially in real space form a highly tunable emergent atomic chain. Engineered lattices in condensed matter physics, such as cold-atom optical lattices or photonic crystals, can have properties that are fundamentally different from those of naturally occurring electronic crystals. We report a novel type of artificial quantum matter lattice. Our lattice is a multilayer heterostructure built from alternating thin films of topological and trivial insulators. Each interface within the heterostructure hosts a set of topologically protected interface states, and by making the layers sufficiently thin, we demonstrate for the first time a hybridization of interface states across layers. In this way, our heterostructure forms an emergent atomic chain, where the interfaces act as lattice sites and the interface states act as atomic orbitals, as seen from our measurements by angle-resolved photoemission spectroscopy. By changing the composition of the heterostructure, we can directly control hopping between lattice sites. We realize a topological and a trivial phase in our superlattice band structure. We argue that the superlattice may be characterized in a significant way by a one-dimensional topological invariant, closely related to the invariant of the Su-Schrieffer-Heeger model. Our topological insulator heterostructure demonstrates a novel experimental platform where we can engineer band structures by directly controlling how electrons hop between lattice sites.