Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Significant enhancement of ferromagnetism in Zn$_{1-x}$Cr$_{x}$Te doped
  with iodine as an n-type dopant   The effect of additional doping of charge impurities was investigated in a
ferromagnetic semiconductor Zn$_{1-x}$Cr$_{x}$Te. It was found that the doping
of iodine, which is expected to act as an n-type dopant in ZnTe, brought about
a drastic enhancement of the ferromagnetism in Zn$_{1-x}$Cr$_{x}$Te while the
grown films remained electrically insulating. In particular, at a fixed Cr
composition of x = 0.05, the ferromagnetic transition temperature Tc increased
up to 300K at maximum due to the iodine doping from Tc = 30K of the undoped
counterpart, while the ferromagnetism disappeared due to the doping of nitrogen
as a p-type dopant. The observed systematic correlation of ferromagnetism with
the doping of charge impurities of both p- and n-type, suggesting a key role of
the position of Fermi level within the impurity d-state, is discussed on the
basis of the double exchange interaction as a mechanism of ferromagnetism in
this material.

16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th