Eur. Phys. J. B 74, 463–466 (2010)
DOI: 10.1140/epjb/e2010-00124-4
Regular Article
T
HE
E
UROPEAN
P
HYSICAL
J
OURNAL
B
Electronic structure of C co-doped (Ga, Fe)N-based diluted
magnetic semiconductors
O. Mounkachi
1, 5
,A.Benyoussef
1, 3,4
,A.ElKenz
1,a
,E.H.Saidi
2, 3,4
, and E.K. Hlil
5
1
Laboratoire de Magn´etisme et de Physique des Hautes
´
Energies D´epartement de Physique, B.P. 1014, Facult´e des Sciences,
Rabat, Morocco
2
Laboratoire de Physique des Hautes Energies D´epartement de physique, B.P. 1014, Facult´e des Sciences, Rabat, Morocco
3
The Institute for Nanomaterials and Nanotechnology, INANOTECH, Rabat, Morocco
4
Hassan II Academy of Sciences and Technology, Rabat, Morocco
5
Institut N´eel, MCMF, CNRS, B.P. 166, 38042 Grenoble Cedex, France
Received 17 November 2009 / Received in final form 23 February 2010
Published online 13 April 2010 –
c
EDP Sciences, Societ`a Italiana di Fisica, Springer-Verlag 2010
Abstract. We report results of the study on GaN doped with Fe and co-doped with Carbon (C), for ac-
ceptors defect, making use of the spin-polarized relativistic Korringa-Kohn-Rostoker coherent-potential
approximation method. In order to understand and to explain the half-metallicity and ferromagnetism
stability, observed in Ga
0.95
Fe
0.05
N with acceptor defects, we calculated the electronic structure and mag-
netic properties of p-type Ga
0.95
Fe
0.05
N. Furthermore, comparison between the electronic structure of the
substitutional and interstitial carbon in (Ga, Fe)N is also given. Mechanism of exchange interaction be-
tween magnetic ions in Ga
0.95
Fe
0.05
N with acceptor defect is investigated. The hyperfine interaction has
been calculated for the disordered alloy systems Ga
0.95
Fe
0.05
N
1−x
C
x
(0.01≤ x ≤0.08).
1 Introduction
Spintronics was proposed as an alternative to the tra-
ditional semiconductor electronics [1]. Development of
ferromagnetic semiconductors is one of the most ac-
tive researches in this field. For III-V diluted magnetic
semiconductors most of the past attention was focused
on the (Ga, Mn)As and (Ga, Mn)N systems and as
promising work bench for future applications in spintron-
ics [2–8]. Only little is known about the (Ga, Fe)N ma-
terials system. One of the major technical barriers that
must be overcome to realize the practical implementa-
tion of spintronic devices is the development of suitable
spin-polarized materials that will effectively allow spin-
polarized carriers to be injected, transported, and ma-
nipulated. The magnetic properties of p-type (Ga, Fe)N
implanted with Fe ions were reported, showing a ferro-
magnetic response evidenced by magnetization hystere-
sis loops persisting, depending on the provided dose [8]
up to room temperature [9,10]. Tao Zhi-Kuo et al. [11]
show that the ferromagnetism may originate from carrier-
mediated Fe-doped GaN diluted magnetic semiconduc-
tors or nanoscale iron clusters and Fe–N compounds. Sato
et al. [12] had carried out KKR-CPA calculation in ran-
domly substituted Fe impurities in GaN and found a spin-
glass state to be stable for any concentration of Fe in
a
e-mail: elkenz@fsr.ac.ma
Ga
1−x
Fe
x
N. In order to stabilize the ferromagnetic phase,
it is necessary to insert carriers into the system, accord-
ing to the Zener model approach by Dietel et al. [13].
The stabilization of ferromagnetism will be more efficient
when the carriers are holes instead of electrons. Recently
Mounkachi et al. [14] show that the stabilization of fer-
romagnetism will be more efficient when the carriers are
holes with acceptor defects like Ga vacancies for p-type
(Ga, Fe)N, they show that this ferromagnetic stabiliza-
tion is due to double exchange and show that the ground
state of (Ga, Fe)N changes from anti-ferromagnetic to fer-
romagnetic by Ga vacancies. Recently a similar experi-
mental work has been done on the effect of co-doping of
(Ga, Fe)N with Si and Mg, which shows that co-doping
with Si is donors and Mg is acceptors, and also shows
that the aggregation of Fe ions can be diminished or even
prevented by doping with either Si donors or Mg accep-
tors and also this co-doping can hampers the nanocrystal
assembling [15].
In this paper, the electronic structure and magnetic
properties of Ga
0.95
Fe
0.05
N
1−x
C
x
are investigated by the
first principles calculations and a material of new TM
GaN-based DMS is proposed. Our calculations are based
on KKR-CPA method within the density functional the-
ory (DFT). Mechanism of exchange interaction between
magnetic ions in Ga
0.95
Fe
0.05
N with acceptor defects is in-
vestigated. The hyperfine interaction has been calculated
for the disordered alloy systems p-type Ga
0.95
Fe
0.05
N.