Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structural and electronic properties of the random alloy
  ZnSe$_x$S$_{1-x}$   In this article we employ density functional theory in the generalized
gradient approximation to investigate the structural and electronic properties
of the solid solution alloy $\text{Zn}\text{Se}_x\text{S}_{1-x}$ in the
wurtzite structure. We analyzed the character of the bond lengths and angles at
the atomic scale, using a supercell approach that does not impose any
constraint on the crystal potential. We show that the bond lengths of pristine
ZnS and ZnSe compounds are almost preserved between nearest neighbors, which is
different from what would be anticipated if Vegard's law were valid at the
atomic level. We also show that bond lengths start behaving in accordance to
Vegard's law from the third shell of nearest neighbors onward, which in turn
determines the average lattice parameters of the alloys determined by
diffraction experiments. Fundamental building blocks around the anions are
identified and are shown to be non-rigid but still volume preserving. Finally,
the geometrical analysis is connected to the trend exhibited by the electronic
structure, and in particular by the band gap. The latter is found to exhibit a
small deviation from the linearity with respect to the Se concentration, in
accordance to available experimental data. By assuming a quadratic dependence,
we can extract a bowing parameter and analyze various contributions to it with
various calculations under selected constraints. The structural deformation in
response to the doping process is shown to be the driving force behind the
deviation from linearity. The difference in stiffness between ZnS and ZnSe is
showed to play a key role in the asymmetric behavior of the bowing parameter
observed in the S-rich and Se-rich regions.

19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex