Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Collinear to Anti-collinear Quantum Phase Transition by Vacancies   We study static vacancies in the collinear magnetic phase of a frustrated
Heisenberg $J_1$-$J_2$ model. It is found that vacancies can rapidly suppress
the collinear antiferromagnetic state (CAFM)and generate a new magnetic phase,
an anti-collinear magnetic phase (A-CAFM), due to magnetic frustration. We
investigate the quantum phase transition between these two states by studying a
variety of vacancy superlattices. We argue that the anti-collinear magnetic
phase can exist in iron-based superconductors in the absence of any preceding
structural transitions and an observation of this novel phase will
unambiguously resolve the relation between the magnetic and structural
transitions in these materials.

27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con