Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flexocoupling impact on the size effects of piezo- response and
  conductance in mixed-type ferroelectrics-semiconductors under applied
  pressure   Flexocoupling impact on the size effects of the spontaneous polarization,
effective piezo-response, elastic strain and compliance, carrier concentration
and piezo-conductance have been calculated in thin films of ferroelectric
semiconductors with mixed-type conductivity under applied pressure. Analysis of
the self-consistent calculation results revealed that the thickness dependences
of aforementioned physical quantities, calculated at zero and nonzero
flexoelectric couplings, are very similar under zero applied pressure, but
become strongly different under the application of external pressure pext. At
that the differences become noticeably stronger for the film surface under
compression than under tension. The impact of the Vegard mechanism on the size
effects is weaker in comparison with flexocoupling except for the thickness
dependence of the piezo-conductance. Without flexoelectric coupling the studied
physical quantities manifest conventional peculiarities that are characteristic
of the size-induced phase transitions. Namely, when the film thickness h
approaches the critical thickness hcr the transition to paraelectric phase
occurs. The combined effect of flexoelectric coupling and external pressure
induces polarizations at the film surfaces, which cause the electric built-in
field that destroys the thickness-induced phase transition to paraelectric
phase at h= hcr and induces the electret-like state with irreversible
spontaneous polarization at h<hcr. The built-in field leads to noticeable
increase of the average strain and elastic compliance under the film thickness
decrease below hcr that scales as 1/h at small thicknesses h. The changes of
the electron concentration by several orders of magnitude under positive or
negative pressures can lead to the occurrence of high- or low-conductivity
states, i.e. the nonvolatile piezo-resistive switching.

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The categories of this paper are: math
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom