Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamics of Symmetry-Breaking Stacking Boundaries in Bilayer MoS2   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.

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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: math
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The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th