Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generating nanoscale and atomically-sharp p-n junctions in graphene via
  monolayer-vacancy-island engineering of Cu surface   Creation of high quality p-n junctions in graphene monolayer is vital in
studying many exotic phenomena of massless Dirac fermions. However, even with
the fast progress of graphene technology for more than ten years, it remains
conspicuously difficult to generate nanoscale and atomically-sharp p-n
junctions in graphene. Here, we employ monolayer-vacancy-island engineering of
Cu surface to realize nanoscale p-n junctions with atomically-sharp boundaries
in graphene monolayer. The variation of graphene-Cu separations around the
edges of the Cu monolayer-vacancy-island affects the positions of the Dirac
point in graphene, which consequently lead to atomically-sharp p-n junctions
with the height as high as 660 meV in graphene. The generated sharp p-n
junctions isolate the graphene above the Cu monolayer-vacancy-island as
nanoscale graphene quantum dots (GQDs) in a continuous graphene sheet. Massless
Dirac fermions are confined by the p-n junctions for a finite time to form
quasi-bound states in the GQDs. By using scanning tunneling microscopy, we
observe resonances of quasi-bound states in the GQDs with various sizes and
directly visualize effects of geometries of the GQDs on the quantum
interference patterns of the quasi-bound states, which allow us to test the
quantum electron optics based on graphene in atomic scale.

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The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph