Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Van der Waals Epitaxy on Freestanding Monolayer Graphene Membrane by MBE   Research on two-dimensional materials has expanded over the past two decades
to become a central theme in condensed matter research today. Significant
advances have been made in the synthesis and subsequent reassembly of these
materials using mechanical methods into a vast array of hybrid structures with
novel properties and ever-increasing potential applications. The key hurdles in
realizing this potential are the challenges in controlling the atomic structure
of these layered hybrid materials and the difficulties in harnessing their
unique functionality with existing semiconductor nanofabrication techniques.
Here we report on high-quality van der Waals epitaxial growth and
characterization of a layered topological insulator on freestanding monolayer
graphene transferred to different mechanical supports. This templated synthesis
approach enables direct interrogation of interfacial atomic structure of these
as-grown hybrid structures and opens a route towards creating device structures
with more traditional semiconductor nanofabrication techniques.

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The categories of this paper are: nlin
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org