Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A first-principles systematic study of GaAs nanowires   In this paper we present a detailed analysis of the atomic and electronic
structure of GaAs nanowires using first-principles pseudopotential
calculations. We consider six different types of nanowires with different
diameters all grown along [111] direction and reveal interesting trends between
cohesive energy and nanowire type with varying diameters. Generally, the
average cohesive energy of nanowires with wurtzite stacking is higher than
those with zinc blende stacking for small diameters. We found that most of the
bare nanowires considered here are semiconducting and continue to be
semiconducting upon the passivation of surface dangling bonds with hydrogen
atom. However, the surface states associated with the surface atoms having two
dangling bonds in zinc blende stacking occur in the band gap and can decrease
the band gap to change the nanowire from semiconducting to metallic state.
These nanowires become semiconducting upon hydrogen passivation. Even if the
band gap of some nanowires decreases with increasing diameter and hence reveals
the quantum confinement effect, generally the band gap variation is rather
complex and depends on the type and geometry, diameter, type of relaxation and
also whether the dangling bonds of surface atoms are saturated with hydrogen.

35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph