Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Giant flexoelectric effect in two-dimensional boron-nitride sheets   We find, with the use of first-principles calculations, that a
single-atom-thick boron-nitride (BN) sheet exhibits an unusual nonlinear
electromechanical effect: it becomes macroscopically polarized when bent
out-of-plane. The direction of the induced polarization is in the plane of the
film and it depends non-analitically on the corrugation wave vector k. The
magnitude of the polarization can reach very high values in spite of being at
least quadratic in atomic displacements due to BN sheets being able to tolerate
large mechanical strains. The discovered effect can find many applications, in
particular, in a new type of efficient and reliable nanogenerators.

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The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
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The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat