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Physica B
journal homepage: www.elsevier.com/locate/physb
Theoretical investigation of structural, mechanical and electronic properties
of GaAs
1-x
N
x
alloys under ambient and high pressure
Jian Li
a
, Xiuxun Han
a,b,
⁎
, Chen Dong
a,c
, Changzeng Fan
d
a
Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China
b
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China
c
University of Chinese Academy of Sciences, Beijing 100080, PR China
d
State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, PR China
ARTICLE INFO
Keywords:
First-principles calculations
GaAs
1-x
N
x
alloys
High pressure
Dilute nitrides
N concentration
Band gap
ABSTRACT
Using first-principles total energy calculations, we have studied the structural, mechanical and electronic
properties of GaAs
1-x
N
x
ternary semiconductor alloys with the zinc-blende crystal structure over the whole
nitrogen concentration range (with x from 0 to 1) within density functional theory (DFT) framework. To obtain
the ideal band gap, we employ the semi-empirical approach called local density approximation plus the multi-
orbital mean-field Hubbard model (LDA+U). The calculated results illustrate the varying lattice constants and
band gap in GaAs
1-x
N
x
alloys as functions of the nitrogen concentration x. According to the pressure dependence
of the lattice constants and volume, the higher N concentration alloy exhibits the better anti-compressibility. In
addition, an increasing band gap is predicted under 20 GPa pressure for GaAs
1-x
N
x
alloys.
1. Introduction
In recent years, the study of nitride-based III–V compound
semiconductors continues to attract intense attention. It is well known
that the band gap of GaN is significantly larger than that of GaAs.
However, even if a small amount of N is incorporated into GaAs, the
band gap of GaAsN dramatically reduces. The strong dependence of
band gap on the N incorporation makes GaAsN related alloys im-
portant materials for high-efficiency solar cell, linear and nonlinear
optoelectronic devices within the commercially interesting wavelengths
[1]. Further studies relate such an unusual feature to the existence of a
giant band gap bowing coefficient [2,3]. Most often, the band gap
bowing parameter for many ternary semiconductor alloys is caused by
the disorder effect [4–6], which leads to significant degradation in
optoelectronic properties. Except for the large reduction of the energy
gap and its composition-dependent bowing parameter [7], the relevant
theoretical [8] and experimental [9,10] research of N alloying in GaAs
also show a decrease of the lattice [11] and elastic constants [12].G.
Stenuit and S. Fahy [13] have investigated the lattice and elastic
constants in GaAs
1-x
N
x
alloys as functions of the nitrogen concentra-
tion x using first-principles density functional theory, including the
normal and split-interstitial substitutions. Further comprehensive
work concerning the mechanical properties of ternary GaAsN alloys
is still needed.
Furthermore, pressure is a pivotal factor that determines the status
of materials, and researches into materials under high pressure are
becoming feasible due to the rapid development of the diamond anvil
technique. Since a sudden change in the arrangement of the atoms may
occur under applied pressure, the properties of the high-pressure
phases may be quite different from those under normal conditions.
Because of the existence of the nitrogen element, the compressive
property of the alloy might also be altered. Although various computa-
tional methods have been employed to study the properties of GaAs
1-
x
N
x
[14–16], to the best of our knowledge, quite little theoretical work
on the related properties of this alloy of interest in the presence of
pressure can be referred so far [17].
This work intends to provide additional information on the physical
properties of the ternary alloys GaAs
1-x
N
x
. Based on the local density
approximation plus the multi-orbital mean-field Hubbard model (LDA
+U) [18], the lattice structure, mechanical and electronic properties are
calculated as functions of nitrogen concentration in the pressure of 0–
20 GPa. The presented results reinforce the deep understanding of
pressure-induced changes in basic properties of ternary alloys GaAs
1-
x
N
x
.
2. Details of calculation
In the present work, all the first-principles calculations are per-
http://dx.doi.org/10.1016/j.physb.2017.09.030
Received 21 June 2017; Received in revised form 9 September 2017; Accepted 11 September 2017
⁎
Corresponding author at: Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
E-mail address: xxhan@licp.cas.cn (X. Han).
Physica B 526 (2017) 1–6
Available online 12 September 2017
0921-4526/ © 2017 Elsevier B.V. All rights reserved.
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