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

Abstract

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.

Authors:
; ; ; ; ORCiD logo; ; ; ; ; ; ; ORCiD logo; ORCiD logo; ORCiD logo; ORCiD logo
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1465222
Alternate Identifier(s):
OSTI ID: 1475489; OSTI ID: 1477419
Grant/Contract Number:  
AC02-05CH11231; AC02-76SF00515; MAT2017-88377-C2-1-R; 306504; EFMA-1542741
Resource Type:
Published Article
Journal Name:
Nature Communications
Additional Journal Information:
Journal Name: Nature Communications Journal Volume: 9 Journal Issue: 1; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Country of Publication:
United Kingdom
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Ugeda, Miguel M., Pulkin, Artem, Tang, Shujie, Ryu, Hyejin, Wu, Quansheng, Zhang, Yi, Wong, Dillon, Pedramrazi, Zahra, Martín-Recio, Ana, Chen, Yi, Wang, Feng, Shen, Zhi-Xun, Mo, Sung-Kwan, Yazyev, Oleg V., and Crommie, Michael F. Observation of topologically protected states at crystalline phase boundaries in single-layer WSe2. United Kingdom: N. p., 2018. Web. https://doi.org/10.1038/s41467-018-05672-w.
Ugeda, Miguel M., Pulkin, Artem, Tang, Shujie, Ryu, Hyejin, Wu, Quansheng, Zhang, Yi, Wong, Dillon, Pedramrazi, Zahra, Martín-Recio, Ana, Chen, Yi, Wang, Feng, Shen, Zhi-Xun, Mo, Sung-Kwan, Yazyev, Oleg V., & Crommie, Michael F. Observation of topologically protected states at crystalline phase boundaries in single-layer WSe2. United Kingdom. https://doi.org/10.1038/s41467-018-05672-w
Ugeda, Miguel M., Pulkin, Artem, Tang, Shujie, Ryu, Hyejin, Wu, Quansheng, Zhang, Yi, Wong, Dillon, Pedramrazi, Zahra, Martín-Recio, Ana, Chen, Yi, Wang, Feng, Shen, Zhi-Xun, Mo, Sung-Kwan, Yazyev, Oleg V., and Crommie, Michael F. Fri . "Observation of topologically protected states at crystalline phase boundaries in single-layer WSe2". United Kingdom. https://doi.org/10.1038/s41467-018-05672-w.
@article{osti_1465222,
title = {Observation of topologically protected states at crystalline phase boundaries in single-layer WSe2},
author = {Ugeda, Miguel M. and Pulkin, Artem and Tang, Shujie and Ryu, Hyejin and Wu, Quansheng and Zhang, Yi and Wong, Dillon and Pedramrazi, Zahra and Martín-Recio, Ana and Chen, Yi and Wang, Feng and Shen, Zhi-Xun and Mo, Sung-Kwan and Yazyev, Oleg V. and Crommie, Michael F.},
abstractNote = {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.},
doi = {10.1038/s41467-018-05672-w},
journal = {Nature Communications},
number = 1,
volume = 9,
place = {United Kingdom},
year = {2018},
month = {8}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1038/s41467-018-05672-w

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Cited by: 12 works
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