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Robust Half-Metallic Magnetism in Two-Dimensional Fe/MoS

Chenghuan Jiang, Yitian Wang, Yehui Zhang, Haowei Wang, Qian Chen, and Jianguo Wan J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.8b06695 • Publication Date (Web): 28 Aug 2018 Downloaded from http://pubs.acs.org on August 30, 2018

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The Journal of Physical Chemistry

Robust Half-Metallic Magnetism in Two-Dimensional Fe/MoS2 Chenghuan Jiang,† Yitian Wang,‡ Yehui Zhang,‡ Haowei Wang,¶ Qian Chen,‡ and Jianguo Wan∗,† †School of Physics, Nanjing University, Nanjing, 210093, P.R.China. ‡School of Physics, Southeast University, Nanjing, 211189, P.R.China. ¶Mechanical Engineering Department, California State University Fullerton, Fullerton, CA 92831, United States. E-mail: [email protected]

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Abstract Exploring two-dimensional (2D) materials with both room temperature ferromagnetic ordering and atomic-thin morphology is of great importance to develop nextgeneration spintronic devices, and becomes a focus of current research. Here, a 2D Fe/MoS2 heterostructure constructed by deposition of Fe atoms on MoS2 is proposed with intriguing magnetic and transport properties based on first-principles calculations. The Fe atoms on MoS2 are ferromagnetic coupled with magnetic moment of ∼ 2.0 µB /atom. Monte Carlo simulations with Heisenberg spin Hamiltonian predict that the Curie temperature can be up to 465 K, which ensures its room temperature applications. Remarkably, over a wide bias range, the 2D Fe/MoS2 exhibits half-metallic property with 100% spin-filter efficiency. In addition, both the 2D morphology and the unique electronic properties persist even when it is coated with h-BN as a capping layer. The fantastic room-temperature ferromagnetism and half-metallicity, together with excellent stabilities, endow 2D Fe/MoS2 a promising material for spintronic related applications.

Introduction Two-dimensional (2D) materials with magnetic ordering are of great potential for diverse applications including data storage, magnetic field sensing and spintronic devices. 1–3 The atomic-thickness enables devices to become highly compact in size, and the 2D morphology also makes them more susceptible to external control. Unfortunately, the reported 2D materials with high stability, such as graphene, 4 h-BN 5 and MoS2 , 6 are all found to be non-magnetic. 7 Although quite amount of 2D magnetic systems were predicted to be easily exfoliable, 8–12 room temperature ferromagnetic ordering (RTFM) has not been experimentally detected as the materials exfoliated down to the monolayer limit. Very recently, Huang et al. 13 demonstrated that monolayer CrI3 is an Ising ferromagnet, which is known to be the first characterization of 2D magnetism in experiment. Bonilla et al. 14 later found ferromag2


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netism with large magnetic moments in 2D VSe2 /van der Waals heterostructures. However, it remains a big challenge to realize atomic-thin material with RTFM. Meanwhile, recent research has shown that 2D forms of non-layered materials can be stabilized with the help of the existing 2D material templates. Wang et al. 15 showed the formation of 2D CuCl nanocrystals epitaxially templated on the surface of monolayer MoS2 . Chen et al. 16 reported the epitaxial growth of 2D Au nanocrystals on graphene. Based on ˇ density functional theory (DFT) calculations, Sljivanˇ canin and Belić 17 further showed that the intercalation of the graphene/MoS2 heterostructure can be used to grow Au hexagonal monolayer, which carries out electronic properties markedly similar to those of the free standing gold monolayer. Hasgmi et al. 18 demonstrated the ferromagnetic ground state in Hf monolayer on the h-BN/Ir(111) surface. These results indicate that the novel 2D-materialstemplating method could be a route towards synthesis of robust 2D forms of non-layered magnetic transition metals, e.g., three single elements display RTFM: Fe, Co and Ni. Zhao et al. reported the formation of Fe monolayer by sealing an entire graphene pore using TEM, which indicates the possibility of synthesizing 2D Fe membrane via above templating method. 19 Here, based on first-principles calculation, we studied the Fe atoms adsorbed on MoS2 , and found that the strong hybridization between Fe and MoS2 results in a Fe monolayer epitaxially templated on MoS2 (Fe/MoS2 ). In particular, the 2D Fe/MoS2 was demonstrated to be RTFM and half-metallicity with 100% spin-polarized transport, which is promising to low-dimensional spintronic devices.

Methods All first-principles calculations were performed within the framework of spin-polarized DFT implemented in the Vienna ab initio Simulation Package. 20 The electron-electron interactions were treated by a general gradient approximation parameterized by Perdew, Burke, and Ernzerhof. 21 The kinetic energy cutoff of 500 eV was set for the plane wave expansion with

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a projected augmented wave method. 22 Van der Waals interaction correction was considered using the method of Grimme (DFT-D3). 23 The climbing-image nudged elastic band (cNEB) method 24 was used to find the minimum-energy path and locate possible transition states of Fe atoms on MoS2 . The artificial interaction between adjacent MoS2 along the non-periodic direction was mitigated by introducing a vacuum of more than 15 ˚ A perpendicular to the slab and in conjunction with the dipole correction. 25 The adsorption energy for each Fe atom (Eads ) was defined as: Eads = (EM oS2 + nEF e − EF en /M oS2 )/n

(1)

Where EM oS2 is the energy of the MoS2 monolayer, EF e is the energy of an isolated Fe atom, and EF en /M oS2 is the optimized total energy of Fe atoms on MoS2 . In this convention of the adsorption energy, positive Eads indicates an exothermic adsorption. Ab initio molecular dynamics(AIMD) simulations were performed under a constant-temperature and volume (NVT) ensemble with the temperature controlled at 300 K by the Nosé-Hoover method 26 and the simulation lasted for 5 ps with a time step of 1 fs. Charge and spin transport properties were done with the QuantumWise ATK code, 27 and the density matrix of the scattering region was calculated self-consistently in the presence of an external bias by means of DFT combined with the nonequilibrium Green function method. 28 More computational details can be found in the Supporting Information.

Results and discussion We first investigated the adsorption of a single Fe atom on the high-symmetry sites of MoS2 surface. The preferential position is Mo-top site (Mo-t) with an adsorption energy of 2.48 eV, followed by the hollow site (h), 2.36 eV, as displayed in Fig. 1(a). This coincides with earlier results from Saidi 29 and Ataca et al., 30 who investigated a series of metal monomers adsorbed on MoS2 . The spin-resolved band structure shows a large intra-atomic exchange splitting (∆ex , ∼0.75 eV) of Fe-3d orbitals, which results in a local magnetic moment of 4


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Figure 1: Optimized geometry structure (a) and spin-resolved band structure (b) of single Fe atom adsorbed on the Mo-top site of MoS2 monolayer. The red and blue bubbles correspond to the Fe-3d orbitals on spin-up and spin-down channels. The insets are the spatial structures of wave functions of a and a∗ states with an iso-surface of 0.005 e˚ A−3 . The Fermi energy is set to zero. ∼ 2.0 µB on Fe atom, as illustrated in Fig. 1(b). The orbitals further split into three groups (e1 , e2 and a) due to the C3v symmetry of Mo-top configuration. In the spin-up channel, the e2 (dxz , dyz ) and a (dz2 ) orbitals of Fe atom strongly hybridize with the S-pz and Mo-dz2 orbitals, e.g., the spatial structures of wave functions in Fig. 1(b) illustrate the bonding and antibonding states (a and a∗ ) results from the hybridization between dz2 orbitals of Fe and underlying Mo atoms. Such heavy hybridizations correspond to strong σ − σ bonding character between Fe and MoS2 , which results in larger adsorption energy than that on graphene or h-BN, 0.79 and 0.11 eV, respectively. 31 In order to investigate the inter-adsorbate and adsorbate-substrate interactions, we further explored the configurations of two and three Fe atoms on MoS2 . Fig. 2(a) shows an energy pathway of one Fe atom diffusing close to another which is located on the Mo-top site. The energetically favorable configuration is two adjacent Mo-top sites. The separated Mo-top configuration is 0.430 eV higher in energy than the ground state, indicating that the interaction between Fe atoms reduces the total energy. In addition, the interaction also 5



Figure 2: Energy pathway of two Fe atoms diffusing on MoS2 (a). The spin density of AFM and FM coupling of two Fe atoms located on the adjacent Mo-top sites (b). The iso-surface value is 0.002 e˚ A−3 . Energy pathway of three Fe atoms from a 3D cluster to a planar triangular configuration on MoS2 (c). The units of all numbers are eV. results in a ferromagnetic (FM) coupling between Fe atoms, see in Fig. 2(b), which is 0.304 eV lower in energy than the antiferromagnetic (AFM) state. Nevertheless, when two atoms further get close to each other with one Fe atom finally raising out of the plane, the total energy goes up by 0.530 eV, indicating that the inter-adsorbate interaction between two Fe atoms is weaker than the adsorbate-substrate interaction. This is also true for the case of three Fe atoms, as shown in Fig. 2(c), where the planar arrangement of Fe atoms on adjacent Mo-top sites is the preferential configuration. We then focused on the 2D Fe/MoS2 , where a Fe monolayer is epitaxially templated on all the Mo-top sites of MoS2 . As presented in Fig. 3, the optimized structure maintains the C3v symmetry with the lattice constant of 3.14 ˚ A. Every Fe bonds to the underlying Mo, as well as to three surrounding S atoms, with bond length of 2.85 ˚ A and 2.17 ˚ A, respectively. The adsorption energy here is quite larger than that of single atom adsorbed configuration ( 3.80 v.s. 2.48 eV/Fe) because of the introduced Fe-Fe interaction. It should be noted that

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Table 1: Energy difference ∆E = EAF M − EF M of 2D Fe/MoS2

∆E/Fe (eV)

FM

AFM1

AFM2

AFM3

0.000

0.150

0.144

0.075

the cohesive energy (Ecoh ) of Fe in bulk phase is 4.28 eV, which is larger than the adsorption energy of Fe in 2D Fe/MoS2 (3.80 eV). This indicates that the 2D Fe/MoS2 should not be the global minimum in energy among all the Fe/MoS2 systems. According to the study by Saidi, 29 the ratio of Eads /Ecoh ≈ 0.89 with diffusion barriers ≈ 0.8 eV (see Fig. 2) should make Fe follow a Stranski-Krastanov growth mode with small 3D clusters dispersed on MoS2 . However, Al Balushi and co-workers recently reported a migration-enhanced encapsulation growth (MEEG) technique. 32 By using graphene as a capping and stabilizing layer, they had successfully synthesized 2D forms of GaN on the SiC substrate. This provides inspiration for the synthesis of the 2D Fe/MoS2 . In addition, we calculated the total energy of FM and three AFM states, see Fig. 3(b-e). And the energy differences between AFM and FM states (∆E = EAF M − EF M ) in Table 1 indicate that the FM state of 2D Fe/MoS2 is energetically preferred. As indicated in Fig. 2(b), the FM coupling between Fe-3d orbitals origins from the super exchange interaction mediated by the S-p orbitals between them according to the Goodenough-Kabanori-Anderson (GKA) rule. 33,34 High Curie temperature(Tc ) guarantees the practical applicability for magnetic material. We further estimated the Tc of the Fe/MoS2 by combining Monte Carlo(MC) simulations with Heisenberg spin Hamiltonian,

H = −J1

X

Si · Sj − J2

ij

X

Sk · Sl

(2)

kl

where S is the spin moment of Fe atom with value of 1. J1 and J2 are the nearest and next-nearest neighboring exchange parameters. With the calculated ∆E in Table 1, the J1 and J2 are 35.5 and 1.0 meV in this system. The magnetic moment and specific heat Cv are 7



Figure 3: Optimized structure of Fe/MoS2 (a) and the illustrations of FM and three AFM states (b-e). The dashed lines represent the unit cell. The stimulated magnetic moment and specific heat Cv with respect to the temperature (f). shown in Fig. 3(f) and the Tc is found to be 465 K, implying the RTFM can be achieved in this 2D Fe/MoS2 crystal. (see Supporting Information for more detailed setting up of MC simulations) The total and partial density of states (DOS) are displayed in Fig. 4(a). The DOS near the Fermi level (EF ) is dominated by the contribution of Fe-d orbitals, and the large splitting of these Fe-d states corresponds to the FM coupling in such 2D system. In particular, the DOS indicates that Fe/MoS2 is half-metallicity, i.e., being semiconductor in one spin channel and metal in another. 35 In order to verify its half-metallic nature, we further explored the electronic transport properties in Fe/MoS2 . The spin-resolved transmission spectrums along the zigzag direction with zero-bias are presented in Fig. 4(b). Within the energy range of -0.37 eV < E − EF < 0.43 eV, the spin-up channel is completely suppressed while the spin-down channel is conductive. This energy range is consistent with the energy gap of spin-up channel in DOS. Fig. 4(c) shows the spin-dependent I − V curves in both zigzag and armchair directions. After applying bias voltages, the spin-down current shows metallic 8


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Figure 4: Spin-resolved DOS of Fe/MoS2 (a), the dashed vertical line refers to the Fermi level. Transmission spectrum in zigzag direction with zero bias voltage (b). The I −V curves of Fe/MoS2 in both zigzag and armchair directions (c). behavior, while the spin-up current is completely blocked. Therefore, the I − V character of Fe/MoS2 exhibits a perfect (100%) spin filter efficiency (SFE) with a bias voltage ranging from 0 to 1.2 V, here the SFE is defined as (I↑-I↓)/(I↑+I↓). As the protective coating is a common way to resist the complex environmental influence on low-dimensional devices, we finally investigated the stability of 2D Fe/MoS2 with a capping layer of h-BN (h-BN/Fe/MoS2 ), which is often used as a dielectric material layer in 2D electronic devices. Here we used h-BN rather than graphene because h-BN is a large-gap insulator which is expected to make little influence on the DOS near the Fermi level thus

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Figure 5: Structural snapshots of h-BN/Fe/MoS2 at time of 0 and 5 ps during AIMD simulation under the temperatures of 300 K (a). Partial DOS of h-BN/Fe/MoS2 (b). reserves the half-metallic property of Fe/MoS2 . The vertically arranged 2D h-BN/Fe/MoS2 was modeled using a 5×5 supercell of h-BN on a 4×4 supercell of Fe/MoS2 with lattice parameter of 12.56 ˚ A, where the lattice mismatch for isolated h-BN or Fe/MoS2 is less than 1%. The optimized structure is displayed on the left panel of Fig. 5(a), and the distance between h-BN and Fe/MoS2 varies from 2.20 to 3.00 ˚ A. The AIMD simulation was performed on h-BN/Fe/MoS2 at the room temperature (300 K), and the snapshot of structure at 5 ps is displayed on the right panel of Fig. 5(a). It is clear that the Fe/MoS2 retains the 2D crystal with the capping layer of h-BN. Similar results were also found in Fe/MoS2 covered with graphene (see Supporting Information). This indicates that the stability of 2D Fe/MoS2 could be enhanced by using capping layer, such as h-BN and/or graphene. The binding energy, calculated by subtracting the energy of isolated h-BN and Fe/MoS2 from that of h-BN/Fe/MoS2 , is 0.32 eV/Fe, much smaller than that of isolated Fe atom adsorbed on MoS2 (2.48 eV/Fe). The relatively small binding energy suggests that h-BN bonds to Fe/MoS2 via weak interaction rather than chemical bonding. Thus, the Fe/MoS2 maintains a FM ground state with ∼ 2.0 µB on each Fe atom after capping. In addition, as displayed in Fig. 5(b), the partial DOS of the h-BN/Fe/MoS2 shows that the h-BN makes 10


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almost no contribution to the states in the range of -3.0∼2.0 eV, demonstrating that h-BN coated Fe/MoS2 retains the ferromagnetic and half-metallic properties.

Conclusions In summary, we have investigated the Fe monolayer deposited on MoS2 by using firstprinciples calculations. The 2D MoS2 bonding with Fe monolayer (Fe/MoS2 ) possesses robust ferromagnetic and half-metallic properties with 100% spin-filter efficiency. The Tc is estimated up to 465 K based on Heisenberg spin Hamiltonian model. Finally, the protective layer of h-BN is found has no negative influence on the morphological and electronic structure of 2D Fe/MoS2 . The fantastic RTFM and half-metallicity, together with excellent stabilities, suggest 2D Fe/MoS2 as a promising material to explore flexible spintronic devices and related nanoscale magnetism.

Conflicts of interest The authors declare no competing financial interest.

Acknowledgement This work is supported by the National Key R&D Program of China (Grant No. 2017YFA0403600), Natural Science Funds of China (Grant No. 11404056), Natural Science Funds for University of Jiangsu (Grant No. 17KJB140032) and the Fundamental Research Funds for the Central Universities of China. The authors thank the computational resources at the NJU and National Supercomputing Center in Tianjin.

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Supporting Information Available Computational details including different k-point meshes used in the 2D Brillouin zone integration, the setting up of MC simulation, the AIMD simulation details of Fe/MoS2 covered with graphene and the parameters of transport property calculations within ATK codes. This material is available free of charge via the Internet at http://pubs.acs.org/.

References (1) Iqbal, M. Z.; Qureshi, N. A.; Hussain, G. Recent Advancements in 2D-Materials Interface Based Magnetic Junctions for Spintronics. J. Magn. Magn. Mater. 2018, 457, 110–125. (2) Han, W. Perspectives for Spintronics in 2D Materials. APL Mater. 2016, 4, 032401. (3) Awschalom, D. D.; Flatté, M. E. Challenges for Semiconductor Spintronics. Nat. Phys. 2007, 3, 153–159. (4) Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang, Y.; Dubonos, S. V.; Grigorieva, I. V.; Firsov, A. A. Electric Field Effect in Atomically Thin Carbon Films. Science 2004, 306, 666–669. (5) Zeng, H.; Zhi, C.; Zhang, Z.; Wei, X.; Wang, X.; Guo, W.; Bando, Y.; Golberg, D. White Graphenes: Boron Nitride Nanoribbons via Boron Nitride Nanotube Unwrapping. Nano Lett. 2010, 10, 5049–5055. (6) Radisavljevic, B.; Radenovic, A.; Brivio, J.; Giacometti, i. V.; Kis, A. Single-Layer MoS2 Transistors. Nat. Nanotechnol. 2011, 6, 147–150. (7) Tan, C.; Cao, X.; Wu, X.-J.; He, Q.; Yang, J.; Zhang, X.; Chen, J.; Zhao, W.; Han, S.; Nam, G.-H. et al. Recent Advances in Ultrathin Two-Dimensional Nanomaterials. Chem. Rev. 2017, 117, 6225–6331. 12


Page 12 of 17

Page 13 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(8) Mounet, N.; Gibertini, M.; Schwaller, P.; Campi, D.; Merkys, A.; Marrazzo, A.; Sohier, T.; Castelli, I. E.; Cepellotti, A.; Pizzi, G. et al. Two-Dimensional Materials from High-Throughput Computational Exfoliation of Experimentally Known Compounds. Nat. Nanotechnol. 2018, 13, 246–252. (9) Sun, Z.; Lv, H.; Zhuo, Z.; Jalil, A.; Zhang, W.; Wu, X.; Yang, J. A New Phase of Two-Dimensional ReS2 Sheet with Tunable Magnetism. J. Mater. Chem. C 2018, 6, 1248–1254. (10) Guo, H.; Lu, N.; Wang, L.; Wu, X.; Zeng, X. C. Tuning Electronic and Magnetic Properties of Early Transition-Metal Dichalcogenides via Tensile Strain. J. Phys. Chem. C 2014, 118, 7242–7249. (11) Li, X.; Yang, J. CrXTe3 (X=Si, Ge) Nanosheets: Two Dimensional Intrinsic Ferromagnetic Semiconductors. J. Mater. Chem. C 2014, 2, 7071–7076. (12) Feng, Y.; Wu, X.; Han, J.; Gao, G. Robust Half-Metallicities and Perfect Spin Transport Properties in 2D Transition Metal Dichlorides. J. Mater. Chem. C 2018, 6, 4087–4094. (13) Huang, B.; Clark, G.; Navarro-Moratalla, E.; Klein, D. R.; Cheng, R.; Seyler, K. L.; Zhong, D.; Schmidgall, E.; McGuire, M. A.; Cobden, D. H. et al. Layer-Dependent Ferromagnetism in a van der Waals Crystal Down to the Monolayer Limit. Nature 2017, 546, 270–273. (14) Bonilla, M.; Kolekar, S.; Ma, Y.; Diaz, H. C.; Kalappattil, V.; Das, R.; Eggers, T.; Gutierrez, H. R.; Phan, M.-H.; Batzill, M. Strong Room-Temperature Ferromagnetism in VSe2 Monolayers on van der Waals Substrates. Nat. Nanotechnol. 2018, 13, 289–293. (15) Wang, S.; Li, H.; Zhang, J.; Guo, S.; Xu, W.; Grossman, J. C.; Warner, J. H. Epitaxial Templating of Two-Dimensional Metal Chloride Nanocrystals on Monolayer Molybdenum Disulfide. ACS Nano 2017, 11, 6404–6415.

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(16) Chen, Q.; He, K.; Robertson, A. W.; Kirkland, A. I.; Warner, J. H. Atomic Structure and Dynamics of Epitaxial 2D Crystalline Gold on Graphene at Elevated Temperatures. ACS Nano 2016, 10, 10418–10427. ˇ ˇ Belić, M. Graphene/MoS Heterostructures as Templates for Growing (17) Sljivanˇ canin, Z.; 2 Two-Dimensional Metals: Predictions from Ab Initio Calculations. Phys. Rev. Mater. 2017, 1, 044003. (18) Hashmi, A.; Farooq, M. U.; Khan, I.; Hong, J. Two-Dimensional Honeycomb Hafnene Monolayer: Stability and Magnetism by Structural Transition. Nanoscale 2017, 9, 10038–10043. (19) Zhao, J.; Deng, Q.; Bachmatiuk, A.; Sandeep, G.; Popov, A.; Eckert, J.; R¨ ummeli, M. H. Free-Standing Single-Atom-Thick Iron Membranes Suspended in Graphene Pores. Science 2014, 343, 1228–1232. (20) Kresse, G.; Furthm¨ uller, J. Efficient Iterative Schemes for Ab Initio Total-Energy Calculations Using a Plane-Wave Basis Set. Phys. Rev. B 1996, 54, 11169. (21) Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865. (22) Blöchl, P. E. Projector Augmented-Wave Method. Phys. Rev. B 1994, 50, 17953. (23) Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A Consistent and Accurate Ab Initio Parametrization of Density Functional Dispersion Correction (DFT-D) for the 94 Elements H-Pu. J. Chem. Phys. 2010, 132, 154104. (24) Henkelman, G.; Uberuaga, B. P.; Jónsson, H. A Climbing Image Nudged Elastic Band Method for Finding Saddle Points and Minimum Energy Paths. J. Chem. Phys. 2000, 113, 9901–9904.

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Page 14 of 17

Page 15 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(25) Bengtsson, L. Dipole Correction for Surface Supercell Calculations. Phys. Rev. B 1999, 59, 12301–12304. (26) Bucher, D.; Pierce, L. C. T.; McCammon, J. A.; Markwick, P. R. L. On the Use of Accelerated Molecular Dynamics to Enhance Configurational Sampling in Ab Initio Simulations. J. Chem. Theory Comput. 2011, 7, 890–897. (27) Taylor, J.; Guo, H.; Wang, J. Ab Initio Modeling of Quantum Transport Properties of Molecular Electronic Devices. Phys. Rev. B 2001, 63, 245407. (28) Brandbyge, M.; Mozos, J.-L.; Ordejón, P.; Taylor, J.; Stokbro, K. Density-Functional Method for Nonequilibrium Electron Transport. Phys. Rev. B 2002, 65, 165401. (29) Saidi, W. A. Trends in the Adsorption and Growth Morphology of Metals on the MoS2 (001) Surface. Cryst. Growth Des. 2015, 15, 3190–3200. (30) Ataca, C.; Ciraci, S. Functionalization of Single-Layer MoS2 Honeycomb Structures. J. Phys. Chem. C 2011, 115, 13303–13311. (31) Yazyev, O. V.; Pasquarello, A. Metal Adatoms on Graphene and Hexagonal Boron Nitride: Towards Rational Design of Self-Assembly Templates. Phys. Rev. B 2010, 82, 045407. (32) Al Balushi, Z.; Wang, K.; Ghosh, R.; Vilá, R.; Eichfeld, S.; Caldwell, J.; Qin, X.; Lin, Y.; Desario, P.; Stone, G. et al. Two-Dimensional Gallium Nitride Realized via Graphene Encapsulation. Nat. Mater. 2016, 15, 1166–1171. (33) Anderson, P. W. New Approach to the Theory of Superexchange Interactions. Phys. Rev. 1959, 115, 2–13. (34) Goodenough, J. B. Theory of the Role of Covalence in the Perovskite-Type Manganites [La, M (II)]MnO3 . Phys. Rev. 1955, 100, 564–573.

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(35) Katsnelson, M. I.; Irkhin, V. Y.; Chioncel, L.; Lichtenstein, A. I.; de Groot, R. A. Half-Metallic Ferromagnets: From Band Structure to Many-body Effects. Rev. Mod. Phys. 2008, 80, 315–378.

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Robust Half-Metallic Magnetism in Two ... - ACS Publications

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