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Title: Observation of topologically protected states at crystalline phase boundaries in single-layer WSe2

Journal Article · · Nature Communications
 [1];  [2];  [3];  [4]; ORCiD logo [2];  [5];  [6];  [6];  [7];  [6];  [8]; ORCiD logo [9]; ORCiD logo [10]; ORCiD logo [2]; ORCiD logo [8]
  1. Donostia International Physics Center (DIPC), San Sebastian (Spain); Centro de Fisica de Materiales (CSIC-UPV/EHU), San Sebastian (Spain); Ikerbasque, Bilbao (Spain)
  2. Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Korea Institute of Science and Technology, Seoul (Korea)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Nanjing Univ., Nanjing (China)
  6. Univ. of California, Berkeley, CA (United States)
  7. Univ. of California, Berkeley, CA (United States); Univ. Autonoma de Madrid, Madrid (Spain)
  8. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  9. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)
  10. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Transition metal dichalcogenide materials are unique in the wide variety of structural and electronic phases they exhibit in the two-dimensional limit. Here we show how such polymorphic flexibility can be used to achieve topological states at highly ordered phase boundaries in a new quantum spin Hall insulator (QSHI), 1T'-WSe2. We observe edge states at the crystallographically aligned interface between a quantum spin Hall insulating domain of 1T'-WSe2 and a semiconducting domain of 1H-WSe2 in contiguous single layers. The QSHI nature of single-layer 1T'-WSe2 is verified using angle-resolved photoemission spectroscopy to determine band inversion around a 120 meV energy gap, as well as scanning tunneling spectroscopy to directly image edge-state formation. Using this edge-state geometry we confirm the predicted penetration depth of one-dimensional interface states into the two-dimensional bulk of a QSHI for a well-specified crystallographic direction. In conclusion, these interfaces create opportunities for testing predictions of the microscopic behavior of topologically protected boundary states.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
MAT2017-88377-C2-1-R; AC02-05CH11231; AC02-76SF00515; 306504; EFMA-1542741
OSTI ID:
1465222
Alternate ID(s):
OSTI ID: 1475489; OSTI ID: 1477419
Journal Information:
Nature Communications, Vol. 9, Issue 1; ISSN 2041-1723
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 92 works
Citation information provided by
Web of Science

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Cited By (15)

Raman spectrum of layered jacutingaite (Pt 2 HgSe 3 ) crystals—Experimental and theoretical study journal November 2019
Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2 journal September 2019
Growth and Thermo-driven Crystalline Phase Transition of Metastable Monolayer 1T′-WSe2 Thin Film journal February 2019
Using ligands to control reactivity, size and phase in the colloidal synthesis of WSe 2 nanocrystals journal January 2019
Novel polymorphic phase of two-dimensional VSe 2 : the 1T′ structure and its lattice dynamics journal January 2019
Recent progress of TMD nanomaterials: phase transitions and applications journal January 2020
Evidence for a narrow band gap phase in 1T′ WS 2 nanosheet journal July 2019
Lateral heterostructures and one-dimensional interfaces in 2D transition metal dichalcogenides journal March 2019
Thermodynamically stable octahedral MoS 2 in van der Waals hetero-bilayers journal July 2019
Unified picture of lattice instabilities in metallic transition metal dichalcogenides journal November 2019
Influence of lattice termination on the edge states of the quantum spin Hall insulator monolayer 1 T ′ − WTe 2 journal May 2019
Lateral Interfaces of Transition Metal Dichalcogenides: A Stable Tunable One-Dimensional Physics Platform text January 2018
A Unified Picture of Lattice Instabilities in Metallic Transition Metal Dichalcogenides text January 2019
Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2 text January 2019
Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2 text January 2019