Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exploration of a new reconstructed structure on GaN(0001) surface by
  Bayesian optimization   GaN(0001) surfaces with Ga- and H-adsorbates are fundamental stages for
epitaxial growth of semiconductor thin films. We explore stable surface
structures with nanometer scale by the density-functional calculations combined
with Bayesian optimization, and succeed to reach a single structure with
satisfactorily low mixing enthalpy among hundreds of thousand possible
candidate structures. We find that the obtained structure is free from any
postulated high symmetry previously introduced by human intuition, satisfies
electron counting rule locally, and shows new adsorbate arrangement, reflecting
characteristics of nitride semiconductors.

9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph