Influential Electronic and Magnetic Properties of the Gallium Sulfide

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Influential Electronic and Magnetic Properties of Gallium Sulfide Monolayer by Substitutional Doping Hui Chen, Yan Li, Le Huang, and Jingbo Li J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.5b09635 • Publication Date (Web): 10 Dec 2015 Downloaded from http://pubs.acs.org on December 21, 2015

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The Journal of Physical Chemistry

Influential Electronic and Magnetic Properties of Gallium Sulfide Monolayer by Substitutional Doping Hui Chen, Yan Li*, Le Huang, and Jingbo Li* State Key Laboratory for Superlattice and Microstructure, Institute of Semiconductor, Chinese Academy of Science, Beijing 100083, China The structural, electronic, and magnetic properties of GaS monolayer doped by 12 different kinds of atoms were investigated systemically using first-principles calculations. N is found to be the most promising candidate for p-type doping among dopants at the S site, including nonmetal atoms H, B, C, N, O, and F and transition metal atoms V, Cr, Mn, Fe, Co, and Ni. Transition metal atoms appear to be hardly incorporated in GaS monolayer under either S- or Ga-rich conditions. While the net magnetic moments of doped GaS by nonmetal atoms are either 0 or 1 µB, the value of transition metal dopants decreases from 5 to 0 µB by adding the number of valence electrons from V to Ni. In the case of transition metal dopants at the Ga site, the majority spin states of Cr and Co are located closest to conduction band minimum and valence band maximum, respectively. Magnetic ground states exist in all of the monolayers doped by these impurities. Indirect band gap of pristine GaS monolayer is regulated to be direct from one type of spin channel by introducing B and Mn in S site and V, Fe, Co, and Ni in Ga site. Keywords Defect state

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Direct bandgap Magnetic contribution First-principles calculations I.

Introduction The rapid progress has been made in the field of two-dimensional (2D) graphene in the past

few years. Moreover, the method using to prepare its ultrathin layers provides a valuable insight into other 2D materials.1-11 One kind of these distinct 2D materials is metal chalcogenide GaX (X=S and Se), which appeals particular scientific interest due to its unconventional electrical, mechanical, magnetic, and optical properties, and their great potential in applications on optoelectronics and spintronics device.12-14 On experimental aspect, large size ultrathin layers of GaS and GaSe were synthesized using micromechanical cleavage technique on SiO2/Si substrates.12-18 Meanwhile, 2D single-sheet n-type GaS field-effect transistor (FET) with high ON/OFF current ratio of 104 has been fabricated, which reveals that GaS plays an role in nanoelectronics devices.12 Zn substituted for Ga site in the single crystal has been verified to be effective for GaS near-blue-light emitting devices depending on its acceptor with a deep energy level.17 Moreover, it has been deduced theoretically that the electronic behavior of GaS layered compound can be modified by the thickness of the layers and the band gap of its monolayer decrease drastically as the external strain increases.19 It is known that doping with impurity plays an essential role in nanostructure semiconducting devices.14,

20-37

Recently, it has been

demonstrated that p-type Mg-doped at the Ga site in GaSe can provide more effective carriers by virtue of its lower transition level compared to GaS under the doping concentration of 5.6 at%.29


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Therefore, doping of material is of great importance due to tuning its intrinsic physical and chemical properties. It becomes intriguing if other dopants in GaS monolayer may influence its electronic properties and induce spin-polarization. However, less attention has hitherto been paid to these effects. In this work, we systemically consider the influence of doping with six kinds of nonmetal atoms (H, B, C, N, O, and F) and six kinds of transition metal atoms (V, Cr, Mn, Fe, Co, and Ni) on the electronic and magnetic characters of GaS monolayer by means of first-principles methods. Proper p-type dopant atom is deduced. It is found that S vacancy in GaS monolayer is hard to be occupied by transition metal impurities spontaneously. Additionally, magnetic moments and band gaps can be modulated to various degrees by different substitutional dopants at the S/Ga site, which is expected to provide new possibilities in nanoelectronics and spintronics. II.

Computational method First-principles calculations were carried out employing generalized gradient approximation

(GGA) with Perdew-Burke-Ernzerhof (PBE) formalism38, 39 on the basis of density functional theory (DFT) as implemented in the Vienna ab initio simulation package (VASP).40, 41 Energy cutoff of 520 eV was set in the calculations. A 4×4 supercell containing 64 atoms with one substitution was used to study the doped GaS monolayer. To prevent interaction between adjacent layers, a vacuum space (˃12 Å) was introduced. Monkhorst-Pack special k-point mesh42 of 5×5×1 was chosen for geometry optimization. The convergence criteria used to the electronic self-consistent and ionic relaxation were set to 10-6 eV for energy and 0.02 eV/Å for force, respectively.


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The substitution energy of a particular substitutional dopant Esubs is defined as33, 36, 43-46

Esubs = Etot [GaS + D] − Etot [GaS ] + µhost − µ D where Etot[GaS+D] is the total energy of the GaS monolayer with substitutional atom D, Etot[GaS] is the total energy of a pristine GaS monolayer, while µhost and µD are the chemical potentials of the S (Ga) host and dopant atom, respectively.47-49 For H, N, O, and F, their chemical potentials are chosen to half the total energies of corresponding gas states H2, N2, O2, and F2, respectively. The bulk phases of other dopants are set to determine their chemical potentials. The heat of formation ∆Hf can be expressed as50 bulk ∆H f = µGaS − µGa − µ Sbulk

where µGaS and µGabulk (µSbulk) are the total energy per GaS unit cell containing one formula unit and per Ga (S) atom in its reference phase, respectively. Then, the value of ∆Hf is calculated to be -1.11 eV in DFT-GGA. The value of µhost strongly depends on the given experimental conditions. Two limiting conditions, including Ga- and S-rich situations are taken into account. Under the Ga-rich condition, the Ga chemical potential can be obtained from bulk Ga, namely bulk , and the S chemical potential is µ s = µ sbulk + ∆H f . Analogously, under the S-rich µ Ga = µ Ga

condition, the chemical potential of S equals the energy of its bulk phase, namely µ S = µ Sbulk , and bulk + ∆H f . the chemical potential of Ga is gained by µGa = µGa

III.

Results and discussion

3.1 Substitution at the S site The hexagonal structure of GaS has a repeating unit of S-Ga-Ga-S sheet built by six-atom Ga3S3 rings,12 as illustrated in Fig. 1. In the pristine GaS monolayer, the height of upper S-layer


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relative to the middle of Ga-Ga layer is 2.36 Å. Nonmetal atom replacement happened below the upper S-layer, while metal atoms are located above it, which is similar to the case of substituted MoS2 monolayer.32 This is because the smaller (larger) nonmetal (metal) atomic radius relative to S atom leads to stronger (weaker) interaction between Ga and substitutional atoms. The binding energy Eb can be described as Eb=Etot[GaS+D]-(Evac+ED), where Evac and ED are energies of defective GaS monolayer with vacancy and isolated impurity atom, respectively. As is listed in Table 1, negative binding energies indicate that all the extrinsic nonmetal atoms are energy favorable to the vacant sites. It is worthy to note that the Coulomb interaction between O and d orbital of Ga is unable to influent the accuracy of DFT calculations examined by GGA+U method. While O has the strongest binding energy of -3.15 eV, B has the weakest binding energy of -0.15 eV, which implies that O-doped GaS is the most stable among these dopants. However, the metal atoms are energy unfavorable in the position of S vacancy owing to their positive values of binding energy.


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Figure 1. (a) Schematic structure and (b) side view of the GaS monolayer. The blue, yellow, and red (or green) balls denote the Ga, S, and S (Ga)-substitutional dopant, respectively. hS and hG represent the height between the dopant and middle of Ga-Ga layer. Table 1. Calculated values of GaS monolayer with substitutional dopant at the S site with comparison to undopant: height between the dopant and middle of Ga-Ga layer hS (Å), binding energy Eb (eV), excess charge on dopant ∆ρ (e), the substitution energy under S-rich Esubs, S (eV) and Ga-rich Esubs, Ga (eV) conditions, magnetic moments of the whole defective structure mtotal (µB) and dopant m (µB), and energy differences between magnetic and nonmagnetic states ∆E1 (eV) and between antiferromagnetic and ferromagnetic couplings ∆E2 (meV). Species

hS

Eb

∆ρ

Esubs, S

Esubs, Ga

mtotal

m

∆E1

∆E2

Undopant

2.36

-5.88

0.754

2.063

0.948

…

…

…

…

H

1.62

-0.23

0.368

1.832

0.718

1.00

0.01

-0.100

-163.4

B

1.56

-0.15

0.405

7.424

6.310

1.00

0.14

-0.086

-127.1

C

1.69

-1.80

0.922

5.317

4.202

…

…

…

…

N

1.73

-1.22

1.132

0.842

-0.272

1.00

0.34

-0.124

-8.6

O

1.75

-3.15

1.110

2.317

1.203

…

…

…

…

F

2.02

-0.43

0.727

2.927

1.813

1.00

0.03

-0.090

-12.9

V

3.01

1.74

-0.542

8.597

7.483

5.00

3.56

-0.077

-68.6

Nonmetal

Metal


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Cr

2.90

2.57

-0.511

7.746

6.632

4.00

3.90

-1.386

-247.1

Mn

2.77

2.08

-0.355

7.255

6.140

3.00

3.41

-2.116

-14.3

Fe

2.67

1.02

-0.129

7.183

6.068

2.00

2.37

-1.112

-6.6

Co

2.45

0.51

-0.930

7.549

6.434

1.00

1.19

-0.274

-2.0

Ni

2.51

0.00

-0.829

5.713

4.599

…

…

…

…

Bader analysis is used to predict the charge transfer.51 The excess charge is employed to describe the charge transferring between atoms when they form a compound, which depends on the separation method of charges. It is found that the excess charge ∆ρ on the nonmetal atom is obtained from neighboring atoms, which is similar to S atom in pristine GaS (Table 1). It results from that S vacancy without dopants behaves as n-type semiconductor with extra electrons existing in the conduction band28 and nonmetal atoms are prone to gain electrons. The largest amount of 1.132e transfer from the monolayer to N, whereas the smallest of 0.368e is obtained by H. N atom has only one p electron less than S atom, which results in its strongest ability of acquiring electrons. In contrast, extra electrons transfer from the metal dopants to the monolayer. The metal atoms tend to lose electrons, whereas S vacancy belongs to donor defect, causing that these impurities are unable to exist at the S site spontaneously. Co exchanges the most excess electrons of 0.93e while the smallest amount of 0.129e is subtracted from Fe atom. Tunable electronic properties of GaS monolayer with nonmetal impurities are investigated by total (TDOS) and partial density of states (PDOS), as shown in Fig. 2. It is evident that impurity states localize within the band gap of pristine GaS monolayer except O dopant. O causes little variety in electronic properties of GaS due to its equal amount of valence electrons


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compared to S. It is one of the reasons that lead to be nonmagnetic which is the same as pristine GaS monolayer. In the case of C, it introduces a deep impurity level in band gap, which is related to its four p electrons in the outermost shell. H and F atoms behave as n-type doping in GaS monolayer owing to their extra outermost electrons compared to S and defect states which are located near the conduction band minimum (CBM). The impurity states are primarily attributed to 2p orbitals of dopants and 4p states of neighboring Ga atoms. B and N atoms serve as electron acceptors from GaS, which is caused by their less p electrons than S atom and both majority and minority spin channels which are localized close to the valence band maximum (VBM). For B doping, the defect states are formed by hybridization between B 2p and Ga 4p states. Spinsplitting of N-doped GaS is even larger compared to B-doped. The impurity bands originate from N 2p orbital with a small contribution from the nearest Ga 3d and S 2p states. N becomes the most proper dopant for p-type doping due to the impurity states that is closer to VBM. In addition to considering the substitution energies of foreign atoms listed in Table 1, N has negative Esubs of -0.272 eV under Ga-rich conditions, while Esubs is positive for other dopants. Accordingly, N is expected to be a more appropriate candidate for p-type doping of GaS monolayer. It has been made clear theoretically52,

53

and experimentally54,

55

that N-doped

graphene is a promising candidate for anode materials of lithium ion batteries. By analogy, the similar effects are expected to be applied to GaS monolayer.


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Figure 2. The TDOSs and PDOSs of H, B, C, N, O, and F substituted S site in GaS monolayer. The plane (a) is TDOS. The lowermost plane (b), (c), and (d) are PDOSs of dopant atoms, Ga and S atoms nearest to dopants, respectively. The red, blue, and green curves denote the s, p, and d orbitals, respectively. The vertical dashed lines indicate the Fermi level and are set to zero. In the case of transition metal dopants, their PDOSs are shown in Fig. 3. Their defect levels mainly stem from 3d states of these metal atoms and 4p orbitals of the nearest Ga atoms with a


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small contribution of 3p states of S. Among these, V and Cr induce deep gap states within the band gap. In comparison with nonmetal impurities, neither a promising n-type nor p-type doping in GaS monolayer can be obtained in the extent of transition metal atoms, owing to that the defect levels are far away from both VBM and CBM and Esubs is positive under both S- and Garich conditions. This is another reason why transition metal atoms hardly substitute the S vacant spontaneously.


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Figure 3. TDOSs and PDOSs of V, Cr, Mn, Fe, Co, and Ni substituted S site in GaS monolayer. The plane (a) is TDOS. The (b), (c), and (d) are PDOSs of foreign atoms, Ga and S atoms closest to dopants, respectively. The red, blue, and green curves denote the s, p, and d orbitals of these atoms, respectively. The vertical dashed lines stand for the Fermi level and are set to zero. It is well known that the pristine GaS monolayer is a nonmagnetic indirect band gap semiconductor with calculated gap of 2.58 eV from neighboring Γ to M point.19, 28 No halfmetallic character is performed in GaS monolayer doped with any impurities. Interestingly, it can be found in Fig. 4 that B-substituted GaS monolayer is a semiconductor with a direct band gap of 1.54 eV along the Γ-Γ direction for up-spin channel and indirect band gap from Γ to M point for down-spin channel. The sheet with Mn substitution behaves as an indirect semiconductor along the K-M direction for up-spin channel and direct with band gap of 1.41 eV at Γ for down-spin channel. Hence, GaS monolayer causes indirect-to-direct band gap transition by introducing B and Mn dopants from up- and down-spin channel, respectively, which is desired for nanoelectronic applications.


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Figure 4. Band structures of GaS monolayer with B and Mn impurities. Red and blue curves represent up- and down-spin channels, respectively. Fermi level is set to zero. Next, the magnetic properties of the doped by nonmetal and transition metal atoms were investigated by DFT. The energy difference (∆E1) between magnetic and nonmagnetic states was calculated and listed in Table 1. While H, B, N, and F substituted GaS monolayer has a magnetic ground state with magnetic moment of 1.0 µB, C and O doped ones possess nonmagnetic ground state, which is alike to the case of impure MoS2 sheet.32 Moreover, the contributions of H, B, N, and F impurities to overall magnetic moments, defined as

m , are 1.0%, 12.3%, 25.4%, m + mtotal

and 2.9%, respectively. It can be found that the total magnetizations of H and F doped systems mainly stem from the nearest Ga, first and second nearest S atoms, as seen in Fig. 5 (a) and (d), respectively. However, B and N doped monolayers show different behavior, as their spin densities are more localized at the neighboring Ga and S atoms. Interestingly, for metal impurities, the magnetic moment decreases with increasing the atomic number from V to Ni, takes the maximum value of 5 µB for V, and degenerates to 0 µB for Ni. Among them, the magnetic moment of GaS doped with a nonmagnetic element V is larger when compared to a magnetic element Cr. This is caused by the larger electronegativity of Cr, which leads to increased interaction between Ga and Cr atoms. This result is further supported by six valence electrons of Cr equally to S, which tends to nonmagnetic state of pristine GaS. Spin density distributions also behave more localized along with acceleration of valence electrons, as illustrated from Fig. 5 (e) to (i). While the spin densities of V and Cr extend to the nearest Ga and S atom, those of Mn and Fe primarily spread on the dopants and neighboring Ga atoms, and that of Co only focuses on the impurity atom. Furthermore, every metal dopant contributes


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comparable ratio to the general magnetization, namely 41.6% for V, 49.4% for Cr, 53.2% for Mn, 54.2% for Fe, and 54.3% for Co, respectively, which are much more than the case of nonmetal doped systems. For determining the magnetic coupling states of nonmetal doped GaS monolayer, the 8×8 supercell doubling the doped structure along X and Y directions was chosen. Both the antiferromagnetic (AFM) and ferromagnetic (FM) coupling between the adjacent unit cells were set for the initial state. It can be found from Table 1 that all the energy differences (∆E2) between AFM and FM states are negative, which means that AFM coupling exist in all nonmetal- and transition metal-substituted GaS monolayer at a distance of 14.35 Å, which resembles MoS2 monolayer with nonmetal atom absorption.34

Figure 5. The spin density isosurfaces (isosurface value=0.001 e/Å3) of H, B, N, F, V, Cr, Mn, Fe, and Co-substituted GaS monolayer. The pink and green colors denote positive and negative values, respectively.


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3.2 Substitution at the Ga site Next, substitutional doping at the Ga site with different transition metal atoms was systemically investigated. These atoms are situated above the upper Ga-layer, when compared to the distance (1.24 Å) between the upper Ga-layer and the middle of Ga-Ga layer for the pristine GaS monolayer. It can be deduced from Table 2 that metal atoms are energetically favorite at the location of Ga vacancy as their binding energies are all negative, especially, the strongest binding energy -3.27 eV is found for V substitution. The calculated formation energy of Ga vacancy is 6.26 eV and higher than S vacancy (5.88 eV), resulting in energetic favor at Ga vacancy substituted by transition metal atoms compared to S vacancy. Bader analysis reveals that the loss of electrons from Ga is 0.813e in undoped monolayer. Once doped, the metal atom also transfers charges to the monolayer. Moreover, the amount of transferred electrons decreases as the increasing atomic number of the dopants, for example, 1.112e for V vs. 0.344e for Ni, which is caused by stronger binding effects of their nucleus on valence electrons and consequent weaker abilities of losing electrons from V to Ni atom.

Table 2. Calculated values of GaS monolayer with transition metal impurity at the Ga site with comparison to undopant: height between impurity and the middle of Ga-Ga layer hGa (Å), binding energy Eb (eV), excess charge on impurity ∆ρ (e), the substitution energy under S-rich Esubs,

S

(eV) and Ga-rich Esubs,

Ga

(eV) conditions, magnetic moments of the structure with

impurity mtotal (µB) and impurity m (µB), and energy difference between magnetic and nonmagnetic structures ∆E1 (eV) and between antiferromagnetic and ferromagnetic couplings ∆E2 (meV).


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Species

hGa

Eb

∆ρ

Esubs, S

Esubs, Ga

mtotal

m

∆E1

∆E2

Undopant

1.24

-6.26

-0.813

2.697

3.811

…

…

…

…

V

1.57

-3.27

-1.112

4.220

5.335

2.00

1.90

-0.761

3.3

Cr

1.62

-1.35

-0.954

4.461

5.575

3.00

2.87

-1.033

-72.0

Mn

1.54

-1.76

-0.851

4.044

5.158

4.00

3.66

-1.413

-5.7

Fe

1.50

-2.46

-0.826

4.339

5.453

5.00

3.46

-0.767

-15.8

Co

1.44

-2.82

-0.428

4.857

5.971

2.00

1.61

-0.588

-20.0

Ni

1.50

-2.13

-0.344

4.220

5.335

1.00

0.66

-0.168

-10.0

Figure 6 indicates electronic properties of transition metal atom substituted Ga site in GaS monolayer via TDOS and PDOS. Defect states of Cr and Mn originate mainly from 3d states of dopants and a small contribution from 4s states of closest Ga and 3p states of S atoms. It can be seen that the majority spin state of Cr appears in the bottom of CBM and closer to it compared to Mn. In the case of Co and Ni, the impurity states stem from 3d orbitals of foreign atoms besides p orbitals of neighboring Ga and S atoms. For Co doping, the majority spin state is located at the top of VBM and closer to it than Ni. V and Fe give rise to deep defect level within the band gap, which are formed by 3d states of impurities with a small amount of 3d states of nearest Ga and 3p states of S atoms. It is also found that the location of defect states moves continuously in the region of band gap as the increasing number of d electrons. The defect states move closer to CBM from V to Cr, then return to VBM from Cr to Co, and finally stay in the position of impurity states for Ni. However, the substitution energy of transition metal dopants ranges from


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4.0 to 6.0 eV under either S-rich or Ga-rich conditions (Table 2), which manifests that these dopants are hard to be integrated into the GaS monolayer spontaneously.

Figure 6. TDOS and PDOS of V, Cr, Mn, Fe, Co, and Ni substituted Ga site in GaS monolayer. The plane (a) is TDOS. The (b), (c), and (d) are PDOS of dopant atoms, Ga and S atoms closest to impurities, respectively. The red, blue, and green lines stand for the s, p, and d orbitals of these atoms, respectively. The vertical dashed lines represent the Fermi level and are set to zero.


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In the case of transition metal atom substituted Ga site, GaS monolayer with V, Fe, and Ni dopants displays semiconductors with direct band gap of 0.73 (M-M), 1.98 (Γ-Γ), and 1.10 eV (Γ-Γ) for up-spin channel, respectively, as is shown in Fig. 7. Besides, Co-substituted GaS monolayer behaves as semiconductor with indirect band gap from Γ to M high symmetry point for up-spin channel and direct band gap of 0.74 eV along M-M direction for down-spin channel. It is worthy to note that Mn incorporated into Ga site is unable to lead to transition from indirect to direct band gap, which is different from substitution for S site. However, half-metallic property is absent alike to metal atoms doped in S vacancy.


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Figure 7. Band structures of GaS monolayer with V, Fe, Co, and Ni substitutions for Ga site. Red and blue lines denote up- and down-spin channels, respectively. Fermi level is moved to zero. Moreover, the substitution for Ga site with transition metal atoms modulates not only electronic properties but also magnetic characters of GaS monolayer. Magnetic ground states are found in all the sheets with these dopants via the energies between magnetic and nonmagnetic states in Table 2. The magnetic moments of the doping sheets increase from 2.0 µB for V to 5.0 µB for Fe, then decrease and return to 2.0 µB for Co, and finally reach 1.0 µB for Ni. The contributions to entire magnetic moments reduce successively, namely 48.7%, 48.9%, 47.8%, 40.9%, 44.6%, and 39.8% for V, Cr, Mn, Fe, Co, and Ni impurities, respectively. Correspondingly, their spin density distributions perform more extensive as the increasing number of valence electrons seen from Fig. 8, which is different from these dopants in S site. They mainly localize on the impurities and neighboring S atom for all dopants, especially with a small extension to the third nearest neighboring S atom for Fe, Co, and Ni. Interestingly, FM states are found only in GaS monolayer doped by V while sheets with other dopants behave as AFM states from energy differences between AFM and FM states in Table 2. This is caused by unpaired 3d electron in V atom, which leads to opposite spin direction at the distance of 14.35 Å.


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Figure 8. The spin density isosurfaces (isosurface value=0.001 e/Å3) of V, Cr, Mn, Fe, Co, and Ni-substituted Ga site in GaS monolayer. The pink and green colors represent positive and negative values, respectively. IV.

Conclusions The structural, electronic, and magnetic characters of the GaS monolayer doped

substitutionally with nonmetal and transition metal atoms have been discussed using firstprinciples calculations. Among substitutional dopants at the S site, N is found to be the best promising candidate for p-type doping because not only its impurity states are closer to VBM but also it has negative substitution energy of -0.272 eV under Ga-rich conditions. However, transition metal dopants can hardly be incorporated into the GaS monolayer spontaneously due to positive binding energy and substitution energy under either S- or Ga-rich conditions. For nonmetal dopants, while H, B, N, and F substitutions have magnetic states with 1.0 µB, C and O doped in it cause nonmagnetic ground state. In the case of transition metal dopants, the magnetic


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moment decreases from 5 to 0 µB along with the increasing valence electrons from V to Ni. For substitutional dopants at the Ga site, the majority spin states of Cr and Co are situated closest to CBM and VBM, respectively. Magnetic ground states are found in all the monolayers with these impurities. Moreover, B and Mn dopants at the S site and V, Fe, Co, and Ni dopants at the Ga site cause the transition from indirect to direct for pristine GaS monolayer band gap from one kind of spin channel. All these show great importance for developing nanoelectronic devices based on GaS monolayer.


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AUTHOR INFORMATION Corresponding Author Yan Li and Jingbo Li Address: State Key Laboratory for Superlattice and Microstructures, Institute of Semiconductor, Chinese Academy Science, No. A35 Tsinghua East Road, Haidian District, Beijing 100083, China Telephone number: 86-010-82304982 E-mail: [email protected] (Y. L); [email protected] (J. L) Author Contributions H. C performed the density functional theory calculations. H. C, Y. L, and L. H wrote the manuscript. J. L guided the work. All authors have read the manuscript.


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ACKNOWLEDGMENT This work was supported by the National Natural Science Foundation of China under Grant No. 91233120 and the National Basic Research Program of China (2011CB921901). Jingbo Li thankfully acknowledge financial support from the CAS/SAFEA International Partnership Program for Creative Research Teams.


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Table of Contents (TOC) Image


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Influential Electronic and Magnetic Properties of the Gallium Sulfide

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