Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Improving the convergence of defect calculations in supercells - an ab
  initio study of the neutral silicon vacancy   We present a systematic methodology for the accurate calculation of defect
structures in supercells which we illustrate with a study of the neutral
vacancy in silicon. This is a prototypical defect which has been studied
extensively using ab initio methods, yet remarkably there is still no consensus
about the energy or structure of this defect, or even whether the nearest
neighbour atoms relax inwards or outwards. In this paper we show that the
differences between previous calculations can be attributed to supercell
convergence errors, and we demonstrate how to systematically reduce each such
source of error. The various sources of scatter in previous theoretical studies
are discussed and a new effect, that of supercell symmetry, is identified. It
is shown that a consistent treatment of this effect is crucial to understanding
the systematic effects of increasing the supercell size. This work therefore
also presents the best converged ab initio study of the neutral silicon vacancy
to date.

2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin