title: A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases.
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.
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Ilya
authors.initials: I
authors.lastname: Belopolski
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Su-Yang
authors.initials: SY
authors.lastname: Xu
authors.affiliation: Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA.
authors.forename: Nikesh
authors.initials: N
authors.lastname: Koirala
authors.affiliation: Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Guang
authors.initials: G
authors.lastname: Bian
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Strocov
authors.affiliation: Department of Physics, National University of Singapore, Singapore 117542, Singapore.
authors.forename: Guoqing
authors.identifier: 0000-0003-1180-3127
authors.initials: G
authors.lastname: Chang
authors.affiliation: Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
authors.forename: Madhab
authors.initials: M
authors.lastname: Neupane
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Nasser
authors.initials: N
authors.lastname: Alidoust
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sanchez
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Brahlek
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.; Physikalisches Institut and Röntgen Center for Complex Material Systems, Universität Würzburg, 97074 Würzburg, Germany.
authors.forename: Victor
authors.initials: V
authors.lastname: Rogalev
authors.affiliation: Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK.
authors.forename: Timur
authors.initials: T
authors.lastname: Kim
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Plumb
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
authors.forename: Chaoyu
authors.initials: C
authors.lastname: Chen
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
authors.forename: François
authors.initials: F
authors.lastname: Bertran
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Le Fèvre
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
authors.forename: Amina
authors.initials: A
authors.lastname: Taleb-Ibrahimi
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
authors.forename: Maria-Carmen
authors.initials: MC
authors.lastname: Asensio
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: Ming
authors.initials: M
authors.lastname: Shi
authors.affiliation: Department of Physics, National University of Singapore, Singapore 117542, Singapore.
authors.forename: Hsin
authors.identifier: 0000-0002-4688-2315
authors.initials: H
authors.lastname: Lin
authors.affiliation: Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK.
authors.forename: Moritz
authors.initials: M
authors.lastname: Hoesch
authors.affiliation: Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA.
authors.forename: Seongshik
authors.initials: S
authors.lastname: Oh
authors.affiliation: Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.; Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, NJ 08544, USA.; Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: M Zahid
authors.initials: MZ
authors.lastname: Hasan
keywords: Dirac fermion; Su-Schriffer-Heeger model; materials science; phyics; topological insulator