Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Imaging graphene moir\'e superlattices via scanning Kelvin probe
  microscopy   Moir\'e superlattices in van der Waals heterostructures are gaining
increasing attention because they offer new opportunities to tailor and explore
unique electronic phenomena when stacking 2D materials with small twist angles.
Here, we reveal local surface potentials associated with stacking domains in
twisted double bilayer graphene (TDBG) moir\'e superlattices. Using a
combination of both lateral Piezoresponse Force Microscopy (LPFM) and Scanning
Kelvin Probe Microscopy (SKPM), we distinguish between Bernal (ABAB) and
rhombohedral (ABCA) stacked graphene and directly correlate these stacking
configurations with local surface potential. We find that the surface potential
of the ABCA domains is ~15 mV higher (smaller work function) than that of the
ABAB domains. First-principles calculations based on density functional theory
further show that the different work functions between ABCA and ABAB domains
arise from the stacking dependent electronic structure. We show that, while the
moir\'e superlattice visualized by LPFM can change with time, imaging the
surface potential distribution via SKPM appears more stable, enabling the
mapping of ABAB and ABCA domains without tip-sample contact-induced effects.
Our results provide a new means to visualize and probe local domain stacking in
moir\'e superlattices along with its impact on electronic properties.

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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ph
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin