Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of electrostatic force on piezoelectric materials under high
  electric field: Impact on GaN-based nanoscale structures   The determination of the electromechanical properties of materials for a
parallel-plate capacitor structure is affected by the electrostatic force
between their electrodes. The corrections induced by this
electric-field-induced stress are usually assumed to be linked to the quadratic
dependence of the strain on the electric field (electrostriction). Here we show
by calculations based on thermodynamic grounds for this simple structure that
the effect of the electrostatic force on piezoelectric materials can lead to
both quadratic and linear corrections through the combination of the
piezoelectric coupling and spontaneous polarization. The case of GaN-based
capacitor nanoscale structures is presented taking into account the boundary
conditions imposed as well as the effect of geometry. The results in this
example point to corrections in the piezoelectric and electrostrictive
coefficients higher than 0.3 pmV-1 and 2.6x10-22 m2V-2, respectively.

23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
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
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga