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 language | English |
|---|---|
| Article number | e1501692 |
| Journal | Science Advances |
| Volume | 3 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2017 |
| Externally published | Yes |
Funding
Work at Princeton University and synchrotron-based ARPES measurements led by Princeton University were supported by the U.S. Department of Energy under Basic Energy Sciences grant no. DE-FG-02-05ER46200 (to M.Z.H.). I.B. acknowledges the support of the NSF Graduate Research Fellowship Program. N.K., M.B., and S.O. were supported by the Emergent Phenomena in Quantum Systems Initiative of the Gordon and Betty Moore Foundation under grant no. GBMF4418 and by the NSF under grant no. NSF-EFMA-1542798. H.L. acknowledges support from the Singapore National Research Foundation under award no. NRF-NRFF2013-03. M.N. was supported by start-up funds from the University of Central Florida. We acknowledge Diamond Light Source, Didcot, U.K., for time on beamline I05 under proposal SI11742-1. We acknowledge measurements carried out at the ADRESS beamline (24) of the Swiss Light Source, Paul Scherrer Institute, Switzerland. We acknowledge J. D. Denlinger, S. K. Mo, and A. V. Fedorov for support at the Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. C.L. was supported by grant no. 11504159 of the National Natural Science Foundation of China (NSFC), grant no. 2016A030313650 of NSFC Guangdong, and project no. JCY20150630145302240 of the Shenzhen Science and Technology Innovations Committee.
| Funders | Funder number |
|---|---|
| National Science Foundation | 1542798 |
| National Science Foundation | |
| U.S. Department of Energy | |
| Gordon and Betty Moore Foundation | NSF-EFMA-1542798, GBMF4418 |
| Gordon and Betty Moore Foundation | |
| Basic Energy Sciences | DE-FG-02-05ER46200 |
| Basic Energy Sciences | |
| Lawrence Berkeley National Laboratory | 11504159 |
| Lawrence Berkeley National Laboratory | |
| Princeton University | |
| University of Central Florida | SI11742-1 |
| University of Central Florida | |
| Canadian Light Source | |
| Intelligence Community Postdoctoral Research Fellowship Program | |
| National Research Foundation Singapore | NRF-NRFF2013-03 |
| National Research Foundation Singapore | |
| National Natural Science Foundation of China | 2016A030313650 |
| National Natural Science Foundation of China | |
| Paul Scherrer Institut |