Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Breakdown of the static approximation for free carrier screening of
  excitons in monolayer semiconductors   We address the problem of free carrier screening of exciton states in
two-dimensional monolayer semiconductors. Basic theoretical considerations are
presented concerning the applicability of the commonly used static
approximation of the screening effect and the implications are discussed. We
show that the low-frequency models lead to a major overestimation of the free
carrier response and are inadequate to describe the screening of strongly bound
excitons in monolayer materials. The presented arguments are consistent with
existing high-level many-body theories and transparently illustrate the
underlying physics.

35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc