A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases

Ilya Belopolski, Su Yang Xu, Nikesh Koirala, Chang Liu, Guang Bian, Vladimir N. Strocov, Guoqing Chang, Madhab Neupane, Nasser Alidoust, Daniel Sanchez, Hao Zheng, Matthew Brahlek, Victor Rogalev, Timur Kim, Nicholas C. Plumb, Chaoyu Chen, François Bertran, Patrick Le Fèvre, Amina Taleb-Ibrahimi, Maria Carmen AsensioMing Shi, Hsin Lin, Moritz Hoesch, Seongshik Oh, M. Zahid Hasan

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

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.

Original languageEnglish (US)
Article numbere1501692
JournalScience Advances
Volume3
Issue number3
DOIs
StatePublished - Mar 2017

All Science Journal Classification (ASJC) codes

  • General

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