Antimonene Oxides: Emerging Tunable Direct Bandgap

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Antimonene Oxides: Emerging Tunable Direct Bandgap Semiconductor and Novel Topological Insulator Haibo Zeng, Shengli Zhang, Wenhan Zhou, Yandong Ma, Jianping Ji, Bo Cai, Shengyuan A. Yang, Zhen Zhu, and Zhongfang Chen Nano Lett., Just Accepted Manuscript • Publication Date (Web): 01 May 2017 Downloaded from http://pubs.acs.org on May 1, 2017

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Antimonene Oxides: Emerging Tunable Direct Bandgap Semiconductor and Novel Topological Insulator Shengli Zhang,1 Wenhan Zhou,1 Yandong Ma,2 Jianping Ji,1 Bo Cai,1 Shengyuan A. Yang,3 Zhen Zhu,4 Zhongfang Chen,5 Haibo Zeng*1 1

Key Laboratory of Advanced Display Materials and Devices, Ministry of Industry and

Information Technology, College of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China 2

Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig,

Linnéstr. 2, 04103 Leipzig, Germany 3

Research Laboratory for Quantum Materials, Singapore University of Technology and Design,

Singapore 487372, Singapore 4

Materials Department, University of California, Santa Barbara, CA 93106, USA

5

Department of Chemistry, Institute for Functional Nanomaterials, University of Puerto Rico, Rio

Piedras, San Juan, PR 00931, USA *Correspondence and requests for materials should be addressed to [email protected]

ACS Paragon Plus Environment

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Abstract Highly stable antimonene, as the cousin of phosphorene from group-VA, has opened up exciting realms in the two-dimensional (2D) materials family. However, pristine antimonene is an indirect band-gap semiconductor, which greatly restricts its applications for optoelectronics devices. Identifying suitable materials, both responsive to incident photons and efficient for carrier transfer, is urgently needed for ultrathin devices. Herein, by means of first principles computations, we found that it is rather feasible to realize a new class of 2D materials with a direct bandgap and high carrier mobility, namely antimonene oxides with different content of oxygen. Moreover, these tunable direct bandgaps cover a wide range from 0 to 2.28 eV, which are crucial for solar cell and photodetector applications. Especially, the antimonene oxide (18Sb-18O) is a 2D topological insulator with a sizable global bandgap of 177 meV, which has a nontrivial Z2 topological invariant in the bulk and the topological states on the edge. Our findings not only introduce new vitality into 2D group-VA materials family and enrich available candidate materials in this field, but also highlight the potential of these 2D semiconductors as appealing ultrathin materials for future flexible electronics and optoelectronics devices.

Keywords Antimonene oxide, 2D Semiconductor, tunable direct bandgap, carrier mobility, topological insulator.


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Developing the next generation optoelectronic devices strongly demands for advanced semiconductors with high sensitivity to incident photons and excellent transport property to approach.1-3 Two-dimensional (2D) materials are promising candidates owing to their unique properties such as ultrathin nature, transparent, flexibility, strong interactions with lights and high carrier mobility.4,5 Meanwhile, the existing quantum confinement along the vertical direction would generate a number of fascinating electronic and optical properties. Recently, a family of 2D crystals, derived from the group-VA layered materials (P, As, Sb, Bi), has emerged with increasing research interests owing to their significant fundamental band gaps. Importantly, distinct from zero band-gap group-IVA (graphene, silicene, germanene, and stanene),6 group-IIIA (borophene), and monoelement hafnene nanosheets,7-9 the semiconducting behavior of group-VA 2D materials can render them as potential candidates for next-generation electronics and optoelectronics devices Among these family members, the first candidate under extensive exploration is phosphorene, which exhibits a direct and tunable bandgap (from 0.3 eV in its bulk to 2.0 eV in a monolayer), and a high hole mobility above 10000 cm2 V-1 S-1.10-13 In 2014, Li et al. successfully fabricated the first field-effect transistor (FETs) based on micrometer-sized flakes of few-layer black phosphorus.10 However, one issue that impedes the practical applications of phosphorene is the difficulty in sample synthesis. 2D phosphorene can be exfoliated from bulk black phosphorus via Scotch tape method or liquid exfoliation method, while 3D black P is obtained from red P under high pressure (10 kbar), high temperature (1,000 °C) conditions. The direct synthesis of atomically thin phosphorene is still a great challenge. The other more serious problem is that the exfoliated monolayer and few-layer phosphorene degrade very fast upon air exposure, limiting their practical applications.14-16 In last two years, as the cousins of phosphorene, the semiconducting group-VA nanosheets (arsenene, antimonene and bismuthene) have triggered intense research interests due to their versatile properties.17-49 An intriguing example is antimonene predicted by zhang et al. in 2015.17 Available theoretical studies revealed many


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peculiar properties, such as thermoelectric response, strain-modified inversion of conduction bands, and perpendicular electric field-induced 2D topological character.17-35 In contrast to puckered armchair-like phosphorene, the most stable antimonene holds buckled honeycomb structure with much stronger spin-orbital coupling (SOC), which brings exotic fundamental properties for photonics and spintronics. Excitingly, the theoretically predicted monolayer and few-layer antimonene were just prepared experimentally by mechanical exfoliation, liquid exfoliation, plasma-assisted process, and vapor deposition techniques, and the fine microstructure of the buckled antimonene has been well characterized (Figure 1a).20-25 With considerable band gap as predicted and experimentally proven high stability, 2D antimonene is expected to be a rather promising and competitive candidate for electronic and optoelectronic applications. However, pristine antimonene monolayer is an indirect band-gap semiconductor, which significantly restricts its applications in optoelectronics such as light emitting diode (LED) or photovoltaic devices, because extra phonon momenta are required to assist the transition and hence result in a relatively lower efficiency of energy conversion compared with the direct band-gap semiconductors.17 On the other hand, the carrier mobility of antimonene nanosheet is lower than that of phosphorene.18 Thus, it is highly desirable to modulate the properties of 2D antimonene to achieve appropriate band gap and higher carrier mobility. Herein, by means of first principles computations, we demonstrate the feasibility to realize a new class of 2D materials, antimonene oxides with different content of oxygen. Interestingly, all these antimonene oxides hold tunable direct bandgaps, which cover a wide range from 0 to 2.28 eV. Simultaneously, the effective electron masses of all antimonene oxides are close to that of monolayer and few-layer black phosphorene (meΓX = 0.15～0.18mo), nearly four times smaller than that of monolayer MoS2 (me = 0.60mo). This suggests that all antimonene oxide systems, similar to 2D black phosphorus, may hold higher electron mobility than monolayer MoS2. Excitingly, antimonene oxide (18Sb-18O) is a 2D topological insulator with a sizable global band gap of 177 meV, and characterized by the nontrivial Z2 topological


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invariant and the topological edge states. Thus, our predictions not only introduce new vitality into 2D group-VA materials family, enriching available candidate materials in this field, but also highlight the potential of these 2D semiconductors as appealing ultrathin materials for future flexibility electronics and optoelectronics devices.

Figure 1 | Two-dimensional pristine antimonene with its band structure, and antimonene oxides (a) TEM image of a successfully synthesized ultrathin antimonene. (b) Electronic band structures of pristine honeycomb antimonene with an indirect band gap calculated at the PBE and HSE06 level. (c) Schematics of the hybridization process between antimonene and oxygen. (d) A sketch map of antimonene oxide.


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The outermost shell of Sb atom has five valence electrons with 5s25p3 configuration. In the pristine honeycomb antimonene, each Sb atom forms sp3 hybridization to produce three bonds with adjacent Sb atoms, leaving the non-bonding lone pair electrons. When connected with oxygen atoms, the lone pair electrons of Sb can be donated to the oxygen atom forming a dative bond, in terms of the Lewis structure. Consequently, both Sb and O atoms fulfill the octet rules (Figure 1), and stable antimonene oxides can be expected. Following the above rationale, we are proposing the family of antimonene oxides with different content of oxygen by means of first principles computations. We adopt one supercell with eighteen Sb atoms. All these antimonene oxides are fully relaxed. Clearly, the dangling oxygen motifs, shown in Figure 1d, are composed of one O atom bonding with only one Sb atom. All the Sb=O bonds are perpendicular to the 2D antimonene plane in order to minimize Coulomb repulsion. Significantly, the Sb lone-pair is captured by the more electronegative O atom, giving rise to an excess of negative charge localized on the O atom (Figure S1). Note that besides the different oxygen concentrations, there are also many different configurations for any specific oxygen concentration. To survey such a complicated situation, we consider representative oxygen concentrations, and examined models with different O arrangements. Our computations show that, for each O concentration, their energies are very close, and their band gaps are nearly same (Figure S2). Thus, in the following discussions, we only present one typical configuration for each oxygen concentration. All the optimized structural parameters of antimonene oxides are shown in Table S1. Clearly, lattice constant a increases with the increase of oxygen concentration. Interestingly, the average Sb=O bond length does not change significantly at different oxygen concentrations. Almost all the Sb=O bond lengths in antimonene oxides are 1.70 Å, except that the Sb=O bond lengths are slightly shorter (1.68 Å) in fully oxidized antimonene. Meanwhile, the standard Sb=O bond lengths in the conventional binary oxides of antimony (Sb2O3, Sb2O4 and Sb2O5),50 approximately 2.00 Å, are calculated in Figure S3 and Table S2. So, one could see that the Sb=O


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bond in 2D antimonene oxide is strong, polar, and short compared with the conventional binary oxides of antimony. For the Sb-Sb bond lengths in antimonene oxide, they increase slightly from 2.76 to 2.93 Å with the increase of oxygen concentration, and the oxidized antimonene still keep the significantly buckled structure (Figure S1). This phenomenon is mainly attributed to a significant difference in Pauling electronegativity of Sb (2.05) and O (3.44). How do such oxidations affect the electronic properties of antimonene? To address this issue, we computed the electronic band structures of 2D antimonene oxides as well as their density of states (DOS) (Figure 2). The pristine antimonene is an indirect band gap semiconductor (band gap of 1.75 eV at the PBE level, see Figure 1b; 2.28 eV at the HSE06 level), its valence band maximum (VBM) locates at Г high-symmetry point, while the conduction band minimum (CBM) is between M and Г Brillouin zone. Interestingly, surface oxidation results in an emerging class of direct band-gap antimonene oxides, with the VBM and CBM both located at the Г high-symmetry point (Figure 2a). Note that it is the introduction of oxygen atoms that promotes the adjustment of energy level, especially for the CBM level. Here, the combination of HSE06 and spin-orbital coupling (SOC) effect has been taken into account in the electronic band structures of antimonene oxides. Our computing results show that the differences of band gaps between PBE and HSE levels are about 0.5 eV for antimonene and its partial oxides (18Sb-nO, n and |p±x,y> (Figures 4c and 4d). Here the subscript ± denotes the parity. For 18Sb-O, without including SOC, the bands near the Fermi level are contributed by the |s-> and |p+x,y> orbitals, and the |s-> orbital locates above the |p+x,y> orbital (Figure 4c). For the 18Sb-xO, increasing the oxygen increases the bond length between the Sb atoms, and weakens the interaction between the Sb atoms, thus decreasing the splitting between the bonding and antibonding states. Consequently, with increasing x in 18Sb-xO, the |s-> orbital would shift towards to the |p+x,y> orbital, which well explains why the energy gap of 18Sb-xO can be continuously tuned by changing the x value. When moving from 18Sb-O to 18Sb-18O, the |s-> orbital shifts below the |p+x,y> orbital (Figure 4d). Because |s-> and |p+x,y> orbitals exhibit different parities, such a band inversion is a nontrivial band inversion, which indicates a topological phase transition. In the inverted band structure, |s-> is occupied, and the degenerate |p+x,y> is half occupied, thereby the system becomes a gapless semiconductor. When including SOC in stage (Figure 4d), the degeneracy of the half-occupied |p+x,y> is lifted and a band gap is opened. Therefore, the nontrivial band topology of 18Sb-18O arises from the crystal field effect.

Figure 5 | Stability of 18Sb-18O antimonene oxide. (a) Phonon band dispersions of


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18Sb-18O monolayer. (b) Selected snapshots of 18Sb-18O nanosheet in MD simulations at 300 K. To further assess the stability of the 18Sb-18O nanosheet, we have computed its phonon spectra along high symmetric lines, as shown in Figure 5a. Clearly, there are no soft phonon modes, indicating that the 18Sb-18O nanosheet is dynamically stable. Furthermore, we have carried out first-principles molecular dynamics (MD) to examine the thermal stability of the 18Sb-18O monolayer. We used a 4×4 supercell and carried out MD simulations for 18Sb-18O monolayer at 300 K. Our calculated results show that the nanosheets do not collapse throughout a 3 ps MD simulation at 300K in Figure 5b, indicating a good thermal stability of the 18Sb-18O monolayer. Besides, we also computed the average formation energy. All the formation energy values are negative, and decrease with increasing oxygen concentration (Figure S6), which indicate that the oxide formation is energetically favored in the presence of O2, and thermodynamically oxides with more oxygen concentrations are more favorable. Herein, we discuss some possible experimental methods for the synthesis of antimonene oxides. Quite recently, pure antimonene have been fabricated experimentally in our and other groups.20-25 Moreover, O-antimonene systems are similar to H-graphene because both of them are one-atom thick sheets terminated by one atom. Thus, we can take the hydrogenation of graphene as an analogy and propose some possible methods for the synthesis of antimonene oxides with concentration controllability and selective-area surface functionalization. Two aspects should be taken into account to realize antimonene oxides. (1) Surface group concentration controllability: (a) One method to synthesize graphane (fully hydrogenated graphene) from graphene has been carried out in a cold hydrogen plasma experiments.66 Via a two-hour exposure to hydrogen plasma, fully hydrogenated graphene (graphane) was prepared. In this way, graphene can be hydrogenated in different extent by shortening the treatment durations and lowering the plasma power.66-68 (b) Utilizing electron radiation to activate hydrogen adsorbents on graphene is another available route to fabricate H-functionalized graphene.69 Radiation power and durations remarkably affect the hydrogenation of the final


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products, and both of these two parameters can be adjusted easily. (c) Via STM technology, hydrogen atoms can be added to the graphene lattice more accurately. Through adjusting the flux of hydrogen and exposure time, graphene can be hydrogenated to different extents. (2) Surface selective-area controllability: Selective-area H-graphene patterns have been fabricated using a photoresist mask in a standard photolithography process or a PMMA mask in an e-beam lithography process.70,71 Especially, it should be emphasized to modify the antimonene lattice with activated oxygen at low temperature. Therefore, electron radiation with oxidation coatings, ultraviolet radiation in air or cold oxygen plasma are all expected to be possible routes to realize the expected O-antimonene systems with controlled O distribution and concentration. To summarize, we have presented first-principles evidence toward the realization of a new class of 2D antimonene oxide materials. Our DFT computations demonstrated that antimonene oxides with different content of oxygen, hold tunable direct bandgaps, which cover a wide range from 0 to 2.28 eV. We observed the small effective electron mass of all antimonene oxides with any oxygen concentration, indicating a high carrier mobility. More interestingly, the antimonene oxide (18Sb-18O) is a 2D topological insulator with a sizable global bandgap of 177 meV, characterized by the nontrivial Z2 topological invariant and the topological edge states. Our findings not only arouse new vitality into 2D group-VA materials family and enrich available candidate materials in this field, but also highlight the potential of these 2D semiconductors as appealing ultrathin materials for future flexible electronics, optoelectronics, and photovoltatics devices. Methods. The structural optimizations and electronic structure calculations are performed in the context of density functional theory as implemented in VASP code.72 Exchange-correlation energies are taken into account by the generalized gradient approximation (GGA) using Perdew-Burke-Ernzerh of functional.73 The wave functions are constructed using a projected augmented wave approach with plane wave cutoff energy of 520 eV. The effect of spin-orbit coupling (SOC) is


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included self-consistently in the electronic structure calculations. The atomic positions and cell parameters are fully optimized using conjugate gradient method without imposing any symmetry. After the optimization process, the maximum residual force on each atom is less than 0.001 eV/Å. The total energies are converged within 10-6 eV/cell. A large vacuum space of 20 Å is set along the c axis, the direction perpendicular to the surface, to avoid any interaction between the layer and its periodic images. The Brillouin zone integration is sampled using a set of 13 × 13 × 1 Monkhorst-Pack k points. Carrier effective masses of antimonene oxides were calculated at the PBE level of theory using the CASTEP code.74 In addition, the stability of all these antimonene oxides can be quantified by calculating the average formation energy, defined as Ef=[ESbmOn-(ESbm+n/2EO2]/(m+n), where m, n is the number of Sb or O atoms in the supercell, and ESbmOn, ESbm, and EO2 are the total energies of the antimonene oxides, antimonene, and the O2 (triplet) molecule, respectively. We have performed first-principle MD simulations within the NVT ensemble with the time step of 1 fs at 300 K. A Nose-Hoover thermostat with the Noose Q ratio parameter of 1 was used to keep the temperature constant. The 4×4 supercell of 18Sb-18O monolayer was equilibrated for 3 ps with 3000 steps.

Notes The authors declare no competing financial interests.

ACKNOWLEDGMENTS This work was financially supported by the National Basic Research Program of China (2014CB931702), NSFC (51572128, 21403109), NSFC-RGC (5151101197), Natural Science Foundation of Jiangsu Province (BK20140769), the Fundamental Research Funds for the Central Universities (No. 30916015106), the Fundamental Research Funds for the Central Universities, and PAPD of Jiangsu Higher Education Institutions, and in USA by DoD (Grant W911NF-15-1-0650) and NSF (Grant EPS-1002410). We also acknowledge Computer Network Information Center


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(Supercomputing center) of Chinese Academy of Sciences (CAS) for allocation of computing resource.

REFERENCES 1. Wang, Q. H., Kalantar-Zadeh, K., Kis, A., Coleman, J. N., Strano, M. S. Nat. Nanotechnol. 2012, 7, 699–712. 2. Lopez-Sanchez, O., Lembke, D., Kayci, M., Radenovic, A., Kis, A. Nat. Nanotechnol. 2013, 8, 497–501. 3. Xia, F., Wang, H., Jia, Y. Nat. Commun. 2014, 5, 4458. 4. Akinwande1, D., Petrone, N., Hone, J. Nat. Commun. 2014, 5, 5678. 5. Xia, F., Wang, H., Xiao, D., Dubey, M., Ramasubramaniam, A. Nat. Photon. 2014, 8, 899–907. 6. Zhao, J., Liu, H., Yu, Z., Quhe, R., Zhou, S., Wang, Y., Liu, C., Zhong, H., Han, N., Lu, J., Yao, Y., Wu, K. Prog. Mater. Sci. 2015, 83, 24–151. 7. Mannix, A. J., Zhou, X. F., Kiraly, B., Wood, J. D., Alducin, D., Myers, B. D., Liu, X. L., Fisher, L. B., Santiago, U., Guest, R. J., et al. Science 2015, 350, 1513–1516. 8. Tai, G., Hu, T., Zhou, Y., Wang, X., Kong, J., Zeng, T., You, Y. C., Wang, Q. Angew. Chem. Int. Ed. 2015, 54, 15473–15477. 9. Li, L. F.; Wang, Y. L.; Xie, S. Y.; Li, X. B.; Wang, Y. Q.; Wu, R. T.; Sun, H. B.; Zhang, S. B.; Gao, H. J. Nano Lett. 2013, 13, 4671-4674. 10. Li, L., Yu, Y., Ye, G. J., Ge, Q., Ou, X., Wu, H., Feng, D. L., Chen, H. L., Zhang, Y. B. Nat. Nanotechnol. 2014, 9, 372–377. 11. Fei, R., Yang, L. Nano. Lett. 2014, 14, 2884–2889. 12. Qiao, J., Kong, X., Hu, Z. X., Yang, F., Ji, W. Nat. Commun. 2014, 5, 4475–4482. 13. Liu, Q., Zhang, X., Abdalla, L. B., Fazzio, A., Zunger, A. Nano. Lett. 2015, 15, 1222–1228. 14. Koenig, S. P., Doganov, R. A., Schmidt, H., Castro Neto, A. H., Özyilmaz, B. Appl. Phys. Lett. 2014, 104, 103106–103109.


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15. Castellanos-Gomez, A., Vicarelli, L., Prada, E., Island, J. O., Narasimha-Acharya, K. L., Blanter, S. I., Groenendijk, D. J., Buscema, M., Steele, G. A., Alvarez, J. V. et al. 2D Mater. 2014, 1, 025001–025020. 16. Chen, X., Wu, Y., Wu, Z., Han, Y., Xu, S., Wang, L., Ye, W., Han, T., He, Y., Cai, Y., Wang, N. Nat. Commun. 2015, 6, 7315. 17. Zhang, S., Yan, Z., Li, Y., Chen, Z., Zeng, H. Angew. Chem. Int. Ed. 2015, 54, 3112–3115. 18. Zhang, S., Xie, M., Li, F., Yan, Z., Li, Y., Kan, E., Liu, W., Chen, Z. F., Zeng, H. B. Angew. Chem. 2016, 128, 1698–1701. 19. Wang, G., Pandey, R., Karna, S. P. ACS Appl. Mater. Interfaces. 2015, 7, 11490−11496. 20. Tsai, H. S., Chen, C. W., Hsiao, C. H., Ouyang, H., Liang, J. H. Chem. Commun. 2016, 52, 8409−8412. 21. Wu, X., Shao, Y., Liu, H., Feng, Z., Wang, Y., Sun, J., Liu, C., Wang, J., Liu, Z., Zhu, S., Wang, Y., Du, S., Shi, Y., Ibrahim, K., Gao, H. Adv. Mater. 2017, 29, 1605407−1605412. 22. Ares, P., Aguilar-Galindo, F., Rodríguez-San-Miguel, D., Aldave, D. A., Díaz-Tendero, S., Alcamí, M., Martín, F., Gómez-Herrero, J., Zamora, F. Adv. Mater. 2016, 28, 6332−6336. 23. Gibaja, C., Rodriguez-San-Miguel, D., Ares, P., Gómez-Herrero, J., Varela, M., Gillen, R., Maultzsch, J., Hauke, F., Hirsch, A, Abellán, G., Zamora, F. Angew. Chem. Int. Ed. 2016, 55, 1−6. 24. Ares, P., Zamora, F., Gomez-Herrero, J. ACS Photonics 2017, 4, 600-605. 25. Ji, J., Song, X., Liu, J., Yan, Z., Huo, C., Zhang, S., Su, M., Liao, L., Wang, W., Ni, Z., Hao, Y., Zeng, H. Nat. Commun. 2016, 7, 13352. 26. Pizzi, G., Gibertini, M., Dib, E., Marzari, N., Iannaccone, G., Fiori, G. Nat. Commun. 2016, 7, 12585. 27. Kamal, C., Ezawa, M. Phys. Rev. B 2015, 91, 085423–085432. 28. Aktük, O. Ü., Özçelik, V. O., Ciraci S. Phys. Rev. B 2015, 91, 235446–235455. 29. Akturk, O. U., Akturk, E., Ciraci, S. Phys. Rev. B 2016, 93, 035450–035458.


Page 18 of 21

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30. Zhao, M., Zhang, X., Li, L. Sci. Rep. 2015, 5, 16108–16114. 31. Zhou, J., Sun, Q., Wang, Q., Kawazoe, Y., Jena, P. Nanoscale 2016, 8, 11202–11209. 32. Zhang, S., Xie, M., Cai, B., Zhang, H., Ma, Y., Chen, Z., Zhu, Z., Hu, Z., Zeng, Z. Phys. Rev. B 2016, 93, 245303–245309. 33. Sun, Q., Dai, Y., Ma, Y., Yin, N., Wei, W., Yu, L., Huang, B. 2D Mater. 2016, 3, 035017–035027. 34. Singh, D., Gupta, S. K., Sonvane, Y., Lukačević, I. J. Mater. Chem. C. 2016, 4, 6386–6390. 35. Kou, L., Ma, Y., Tan, X., Frauenheim, T., Du, A., Smith, S. J. Phys. Chem. C. 2015, 119, 6918−6922. 36. Zhu, Z., Guan, J., Tománek, D. Phys. Rev. B 2015, 91, 161404(R)–161408(R). 37. Zhang, S., Hu, Y., Hu, Z., Cai, B., Zeng, H. Appl. Phys. Lett. 2015, 107, 091902–091905. 38. Zhang, H., Ma, Y., Chen, Z. Nanoscale 2015, 7, 19152–19159. 39. Zeraati, M., Allaei, S. M. V., Sarsari, I. A., Pourfath, M., Donadio, D. Phys. Rev. B 2016, 93, 085424–085429. 40. Nie, Y., Rahman, M., Wang, D., Wang, C., Guo, G. Sci. Rep. 2015, 5, 17980–17985. 41. Özçelik, V. O., Aktürk, O. Ü., Durgun, E., Ciraci, S. Phys. Rev. B 2015, 92, 125420−125427. 42. Lee, J., Tian, W. C., Wang, W. L., Yao, D. X. Sci. Rep. 2015, 5, 11512−11527. 43. Zhang Q., Schwingenschlögl, U. Phys. Rev. B 2016, 93, 045312−045317. 44. Wang, Y., Ji, W., Zhang, C., Li, P., Li, F., Ren, M., Chen, X., Yuan, M., Wang, P. Sci. Rep. 2016, 6, 20342–20349. 45. Zhao, J., Lia, Y., Ma J. Nanoscale 2016, 8, 9657–9666. 46. Wang, D., Chen, L., Shi, C., Wang, X., Cui, G., Zhang, P., Chen, Y. Sci. Rep. 2016, 6, 28487−28493. 47. Lu, Y., Zhou, D., Chang, G., Guan, S., Chen, W., Jiang, Y., Jiang, J., Lin, H., Wang, X., Yang, S. et al. Npj. Comput. Mater. 2016, 2, 16011−26032.


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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

48. Liu, M. Y., Huang, Y., Chen, Q. Y., Cao, C., He, Y. Sci. Rep. 2016, 6, 29114−29126. 49. Tsai, H., Wang, S., Hsiao, C., Chen, C., Ouyang, H., Chueh, Y., Kuo, H., Liang, J. Chem. Mater. 2016, 28, 425−429. 50. Allen, J. P., Carey, J. J., Walsh, A., Scanlon, D. O., Watson, G. W. J. Phys. Chem. C 2013, 117, 14759−14769. 51. Rudenko, A. N., Katsnelson, M. I. Roldán R. Phys. Rev. B 2017, 95, 081407(R)−081412(R). 52. Ramasubramaniam, A. Phys. Rev. B 2012, 86, 115409–115414. 53. Dai, J., Zeng, X. C. Angew. Chem. Int. Ed. 2015, 127, 7682–7686. 54. Fei, R., Yang, Li. Nano. Lett. 2014, 14, 2884−2889. 55. Cai, Y., Zhang, G., Zhang, Y. J. Am. Chem. Soc. 2014, 136, 6269−6275. 56. Liu, H., Neal, A. T., Zhu, Z., Xu, X., Tománek, D., Ye, P. D., Luo, Z. ACS Nano 2014, 8, 4033−4041. 57. Xu, Y., Yan, B., Zhang, H. J., Wang, J., Xu, G., Tang, P., Duan, W., Zhang, S. Phys. Rev. Lett. 2013, 111, 136804−136808. 58. Song, Z., Liu, C. C., Yang, J., Han, J., Ye, M., Fu, B., Yang, Y., Niu, Q., Lu J., Yao, Y. NPG Asia Mater. 2014, 6, e147−e153. 59. Zhang, H., Liu, C. X., Qi, X. L., Dai, X., Fang, Z., Zhang, S. C. Nat. Phys. 2009, 5, 438−442. 60. Liu, Q., Zhang, X., Abdalla, L. B., Fazzio, A., Zunger, A. Nano Lett. 2015, 15, 1222−1228. 61. Zhou, J. J., Feng, W., Liu, C. C., Guan, S., Yao, Y. Nano Lett. 2014, 14, 4767−4771. 62. Ma, Y., Dai, Y., Kou, L., Frauenheim, T., Heine, T. Nano Lett. 2015, 15, 1083−1089. 63. Ma, Y., Kou, L., Dai, Y., Heine, T. Phys. Rev. B 2016, 94, 201104−201109. 64. Ma, Y., Kou, L., Dai, Y., Heine, T. Phys. Rev. B 2007, 93, 235451−235456. 65. Schmiedl, T., Seifert U. Phys. Rev. Lett. 2007, 98, 106803−106806. 66. Elias, D. C., Nair, R. R., Mohiuddin, T. M. G., Morozov, S. V., Blake, P., Halsall,


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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

Nano Letters

M. P., Ferrari, A. C., Boukhvalov, D. W., Katsnelson, M. I., Geim A. K., Novoselov, K. S. Science 2009, 323, 610−613. 67. Burgess, J. S., Matis, B. R., Robinson, J. T., Bulat, F. A., Perkins, F. K., Houston, B. H., Baldwin, J. W. Carbon 2011, 49, 4420−4426. 68. Luo, Z., Yu, T., Kim, K. J., Ni, Z., You, Y., Lim, S., Shen, Z., Wang, S., Lin, J. ACS Nano 2009, 3, 1781−1788. 69. Jones, J. D., Mahajan, K. K., Williams, W. H., Ecton, P. A., Mo, Y., Perez, J. M. Carbon 2010, 48, 2335−2340 70. Sun, Z., Pint, C. L., Marcano, D. C., Zhang, C., Yao, J., Ruan, G., Yan, Z., Hauge, R. H., Tour, J. M. Nat. Commun. 2011, 2, 559. 71. Lee, W. H., Suk, J. W., Chou, H., Lee, J., Hao, Y., Wu, Y., Piner, R., Akinwande, D., Kim, K., Ruoff, R. S. Nano Lett. 2012, 12, 2374−2378. 72. Kresse, G., Furthmüller, J. Comput. Mater. Sci. 1996, 6, 15−50. 73. Perdew, J. P., Burke, L., Ernzerhof, M. Phys. Rev. Lett. 1996, 77, 3865−3868. 74. Refson, K., Tulip, P. R., Clark, S. J. Phys. Rev. B 2006, 73, 155114−155125.


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