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Title: Dynamics of Symmetry-Breaking Stacking Boundaries in Bilayer MoS 2

Abstract

Crystal symmetry of two-dimensional (2D) materials plays an important role in their electronic and optical properties. Engineering symmetry in 2D materials has recently emerged as a promising way to achieve novel properties and functions. The noncentrosymmetric structure of monolayer transition metal dichalcogenides (TMDCs), such as molybdenum disulfide (MoS 2), has allowed for valley control via circularly polarized optical excitation. In bilayer TMDCs, inversion symmetry can be controlled by varying the stacking sequence, thus providing a pathway to engineer valley selectivity. Here, we report the in situ integration of AA' and AB stacked bilayer MoS 2 with different inversion symmetries by creating atomically sharp stacking boundaries between the differently stacked domains, via thermal stimulation and electron irradiation, inside an atomic-resolution scanning transmission electron microscopy. The setup enables us to track the formation and atomic motion of the stacking boundaries in real time and with ultrahigh resolution which enables in-depth analysis on the atomic structure at the boundaries. In conjunction with density functional theory calculations, we establish the dynamics of the boundary nucleation and expansion and further identify metallic boundary states. Our approach provides a means to synthesize domain boundaries with intriguing transport properties and opens up a new avenue for controllingmore » valleytronics in nanoscale domains via real-time patterning of domains with different symmetry properties.« less

Authors:
ORCiD logo [1];  [1]; ORCiD logo [1];  [2];  [2];  [3];  [1];  [1]
  1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  3. Univ. of California, Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1506280
Grant/Contract Number:  
[AC02-05CH11231]
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
[ Journal Volume: 121; Journal Issue: 40]; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Yan, Aiming, Ong, Chin Shen, Qiu, Diana Y., Ophus, Colin, Ciston, Jim, Merino, Christian, Louie, Steven G., and Zettl, Alex. Dynamics of Symmetry-Breaking Stacking Boundaries in Bilayer MoS2. United States: N. p., 2017. Web. doi:10.1021/acs.jpcc.7b08398.
Yan, Aiming, Ong, Chin Shen, Qiu, Diana Y., Ophus, Colin, Ciston, Jim, Merino, Christian, Louie, Steven G., & Zettl, Alex. Dynamics of Symmetry-Breaking Stacking Boundaries in Bilayer MoS2. United States. doi:10.1021/acs.jpcc.7b08398.
Yan, Aiming, Ong, Chin Shen, Qiu, Diana Y., Ophus, Colin, Ciston, Jim, Merino, Christian, Louie, Steven G., and Zettl, Alex. Fri . "Dynamics of Symmetry-Breaking Stacking Boundaries in Bilayer MoS2". United States. doi:10.1021/acs.jpcc.7b08398. https://www.osti.gov/servlets/purl/1506280.
@article{osti_1506280,
title = {Dynamics of Symmetry-Breaking Stacking Boundaries in Bilayer MoS2},
author = {Yan, Aiming and Ong, Chin Shen and Qiu, Diana Y. and Ophus, Colin and Ciston, Jim and Merino, Christian and Louie, Steven G. and Zettl, Alex},
abstractNote = {Crystal symmetry of two-dimensional (2D) materials plays an important role in their electronic and optical properties. Engineering symmetry in 2D materials has recently emerged as a promising way to achieve novel properties and functions. The noncentrosymmetric structure of monolayer transition metal dichalcogenides (TMDCs), such as molybdenum disulfide (MoS2), has allowed for valley control via circularly polarized optical excitation. In bilayer TMDCs, inversion symmetry can be controlled by varying the stacking sequence, thus providing a pathway to engineer valley selectivity. Here, we report the in situ integration of AA' and AB stacked bilayer MoS2 with different inversion symmetries by creating atomically sharp stacking boundaries between the differently stacked domains, via thermal stimulation and electron irradiation, inside an atomic-resolution scanning transmission electron microscopy. The setup enables us to track the formation and atomic motion of the stacking boundaries in real time and with ultrahigh resolution which enables in-depth analysis on the atomic structure at the boundaries. In conjunction with density functional theory calculations, we establish the dynamics of the boundary nucleation and expansion and further identify metallic boundary states. Our approach provides a means to synthesize domain boundaries with intriguing transport properties and opens up a new avenue for controlling valleytronics in nanoscale domains via real-time patterning of domains with different symmetry properties.},
doi = {10.1021/acs.jpcc.7b08398},
journal = {Journal of Physical Chemistry. C},
number = [40],
volume = [121],
place = {United States},
year = {2017},
month = {9}
}

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