Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Influence of Lithium Interstitial Doping on the Optoelectronic
  Properties of NiO and WO$_3$   First principles calculations through density functional theory (DFT)+$U$
method were performed to assess the effect of Li interstitial doping on the
optoelectronic properties of NiO and of cubic, hexagonal, and monoclinic
WO$_3$. The implications on the structural and electronic properties and their
relationship with the optical properties, such as dielectric response and
absorption coefficient in the context of electrochromism, are discussed. Li
interstitial doping (i.e., electron doping) turns these materials metallic-like
even for low Li concentration ($x<0.083$). In metallic-like materials, optical
properties are largely influenced by intraband transitions. Compared to NiO,
Li-doped NiO shows larger absorption in the visible region while, with respect
to WO$_3$, Li-doped WO$_3$ exhibits an increment in absorption in the whole
spectrum, particularly, in the infrared region. These results help to
understand the changes in optical properties observed in electrochromic devices
based on these materials.

36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat