• DOI:10.1126/sciadv.1501692
• Corpus ID: 2655517

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

@article{Belopolski2017ANA,
  title={A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases},
  author={Ilya Belopolski and Su-Yang Xu and Nikesh Koirala and Chang Liu and Guang Bian and Vladimir N. Strocov and Guoqing Chang and Madhab Neupane and Nasser Alidoust and D. Sevilla Sanchez and Hao Zheng and Matthew Brahlek and V. A. Rogalev and Timur K. Kim and Nicholas Clark Plumb and Chaoyu Chen and François Bertran and Patrick Le F{\`e}vre and Amina Taleb-Ibrahimi and Maria Carmen Asensio and Ming Shi and Hsin Lin and Moritz Hoesch and Seongshik Oh and M Zahid Hasan},
  journal={Science Advances},
  year={2017},
  volume={3}
}

• I. Belopolski, Su-Yang Xu, +22 authors M Zahid Hasan
• Published 1 March 2017
• Physics
• Science Advances

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.