Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Intermixing and periodic self-assembly of borophene line defects

Nature Materials volume 17, pages 783–788 (2018)Cite this article

Subjects

Abstract

Two-dimensional (2D) boron (that is, borophene) was recently synthesized following theoretical predictions1,2,3,4,5. Its metallic nature and high in-plane anisotropy combine many of the desirable attributes of graphene6 and monolayer black phosphorus7. As a synthetic 2D material, its structural properties cannot be deduced from bulk boron, which implies that the intrinsic defects of borophene remain unexplored. Here we investigate borophene line defects at the atomic scale with ultrahigh vacuum (UHV) scanning tunnelling microscopy/spectroscopy (STM/STS) and density functional theory (DFT). Under suitable growth conditions, borophene phases that correspond to the v1/6 and v1/5 models are found to intermix and accommodate line defects in each other with structures that match the constituent units of the other phase. These line defects energetically favour spatially periodic self-assembly that gives rise to new borophene phases, which ultimately blurs the distinction between borophene crystals and defects. This phenomenon is unique to borophene as a result of its high in-plane anisotropy and energetically and structurally similar polymorphs. Low-temperature measurements further reveal subtle electronic features that are consistent with a charge density wave (CDW), which are modulated by line defects. This atomic-level understanding is likely to inform ongoing efforts to devise and realize applications based on borophene.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Growth of pristine borophene on Ag(111) thin films.
Fig. 2: Presence of line defects in borophene.
Fig. 3: Atomic structures of borophene line defects.
Fig. 4: Self-assembly of borophene line defects and formation of new phases.
Fig. 5: Electronic modulations at low temperature.

Similar content being viewed by others

References

  1. Mannix, A. J. et al. Synthesis of borophenes: anisotropic, two-dimensional boron polymorphs. Science 350, 1513–1516 (2015).

    Article  Google Scholar 

  2. Feng, B. et al. Experimental realization of two-dimensional boron sheets. Nat. Chem. 8, 563–568 (2016).

    Article  Google Scholar 

  3. Zhang, Z., Yang, Y., Gao, G. & Yakobson, B. I. Two-dimensional boron monolayers mediated by metal substrates. Angew. Chem. Int. Ed. 54, 13022–13026 (2015).

    Article  Google Scholar 

  4. Wu, X. et al. Two-dimensional boron monolayer sheets. ACS Nano 6, 7443–7453 (2012).

    Article  Google Scholar 

  5. Tang, H. & Ismail-Beigi, S. Self-doping in boron sheets from first principles: a route to structural design of metal boride nanostructures. Phys. Rev. B 80, 170 (2009).

    Google Scholar 

  6. Novoselov, K. S. et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).

    Article  Google Scholar 

  7. Liu, X., Ryder, C. R., Wells, S. A. & Hersam, M. C. Resolving the in-plane anisotropic properties of black phosphorus. Small Methods 1, 1700143 (2017).

    Article  Google Scholar 

  8. Mannix, A. J., Kiraly, B., Hersam, M. C. & Guisinger, N. P. Synthesis and chemistry of elemental 2D materials. Nat. Rev. Chem. 1, 0014 (2017).

    Article  Google Scholar 

  9. Zhang, Z. et al. Substrate-induced nanoscale undulations of borophene on silver. Nano Lett. 16, 6622–6627 (2016).

    Article  Google Scholar 

  10. Tsafack, T. & Yakobson, B. I. Thermomechanical analysis of two-dimensional boron monolayers. Phys. Rev. B 93, 165434 (2016).

    Article  Google Scholar 

  11. Wang, H. et al. Strain effects on borophene: ideal strength, negative Poisson’s ratio and phonon instability. New J. Phys. 18, 073016 (2016).

    Article  Google Scholar 

  12. Zhang, Z., Yang, Y., Penev, E. S. & Yakobson, B. I. Elasticity, flexibility, and ideal strength of borophenes. Adv. Funct. Mater. 27, 1605059 (2017).

    Article  Google Scholar 

  13. Liu, X. et al. Self-assembly of electronically abrupt borophene/organic lateral heterostructures. Sci. Adv. 3, e1602356 (2017).

    Article  Google Scholar 

  14. Feng, B. et al. Dirac fermions in borophene. Phys. Rev. Lett. 118, 096401 (2017).

    Article  Google Scholar 

  15. Penev, E. S., Kutana, A. & Yakobson, B. I. Can two-dimensional boron superconduct? Nano Lett. 16, 2522–2526 (2016).

    Article  Google Scholar 

  16. Huang, P. Y. et al. Grains and grain boundaries in single-layer graphene atomic patchwork quilts. Nature 469, 389–392 (2011).

    Article  Google Scholar 

  17. Zhao, L. et al. Visualizing individual nitrogen dopants in monolayer graphene. Science 333, 999–1003 (2011).

    Article  Google Scholar 

  18. van der Zande, A. M. Grains and grain boundaries in highly crystalline monolayer molybdenum disulphide. Nat. Mater. 12, 554–561 (2013).

    Article  Google Scholar 

  19. Liu, X., Balla, I., Bergeron, H. & Hersam, M. C. Point defects and grain boundaries in rotationally commensurate MoS2 on epitaxial graphene. J. Phys. Chem. C 120, 20798–20805 (2016).

    Article  Google Scholar 

  20. Hong, J. et al. Exploring atomic defects in molybdenum disulphide monolayers. Nat. Commun. 6, 6293 (2015).

    Article  Google Scholar 

  21. Muzychenko, D. A., Schouteden, K., Panov, V. I. & Van Haesendonck, C. Formation of Co/Ge intermixing layers after Co deposition on Ge(111)2 × 1 surfaces. Nanotechnology 23, 435605 (2012).

    Article  Google Scholar 

  22. Leibsle, F. M., Dhesi, S. S., Barrett, S. D. & Robinson, A. W. STM observations of Cu(100)−c(2×2)N surfaces: evidence for attractive interactions and an incommensurate c(2×2)structure. Surf. Sci. 317, 309–320 (1994).

    Article  Google Scholar 

  23. Xu, T. T. et al. Crystalline boron nanoribbons: synthesis and characterization. Nano Lett. 4, 963–968 (2004).

    Article  Google Scholar 

  24. Moras, P., Mentes, T. O., Sheverdyaeva, P. M., Locatelli, A. & Carbone, C. Coexistence of multiple silicene phases in silicon grown on Ag(111). J. Phys. Condens. Matter 26, 185001 (2014).

    Article  Google Scholar 

  25. Feng, B. et al. Evidence of silicene in honeycomb structures of silicon on Ag(111). Nano Lett. 12, 3507–3511 (2012).

    Article  Google Scholar 

  26. Zhuang, J. et al. Investigation of electron–phonon coupling in epitaxial silicene by in situ Raman spectroscopy. Phys. Rev. B 91, 161409 (2015).

    Article  Google Scholar 

  27. Guan, J., Zhu, Z. & Tománek, D. High stability of faceted nanotubes and fullerenes of multiphase layered phosphorus: a computational study. Phys. Rev. Lett. 113, 226801 (2014).

    Article  Google Scholar 

  28. Aierken, Y., Leenaerts, O. & Peeters, F. M. Defect-induced faceted blue phosphorene nanotubes. Phys. Rev. B 92, 104104 (2015).

    Article  Google Scholar 

  29. Xiang, P. et al. Metallic borophene polytypes as lightweight anode materials for non-lithium-ion batteries. Phys. Chem. Chem. Phys. 19, 24945–24954 (2017).

    Article  Google Scholar 

  30. Huang, Y., Shirodkar, S. N. & Yakobson, B. I. Two-dimensional boron polymorphs for visible range plasmonics: a first-principles exploration. J. Am. Chem. Soc. 139, 17181–17185 (2017).

    Article  Google Scholar 

  31. Foley, E. T., Yoder, N. L., Guisinger, N. P. & Hersam, M. C. Cryogenic variable temperature ultrahigh vacuum scanning tunneling microscope for single molecule studies on silicon surfaces. Rev. Sci. Instrum. 75, 5280–5287 (2004).

    Article  Google Scholar 

  32. Brockenbrough, R. T. & Lyding, J. W. Inertial tip translator for a scanning tunneling microscope. Rev. Sci. Instrum. 64, 2225–2228 (1993).

    Article  Google Scholar 

Download references

Acknowledgements

X.L. and M.C.H. acknowledge support from the Office of Naval Research (ONR N00014-17-1-2993) and the National Science Foundation Materials Research Science and Engineering Center (NSF DMR-1720139). The computational work at Rice University was supported by the Army Research Office (W911NF-16-1-0255) and by the Robert Welch Foundation (C-1590); Z.Z. acknowledges NSFC-11772153 support at a later stage. Z.Z., L.W. and B.I.Y. also acknowledge support by the US DOE Office of Science (DOE DE-SC0012547) and the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures (no. MCMS-0415K01). X.L. further acknowledges support from a Ryan Fellowship that is administered through the Northwestern University International Institute for Nanotechnology. The authors thank A. J. Mannix, M. Han, I. Balla, S. Li, E. S. Penev and Q. Ruan for valuable discussions.

Author information

Authors and Affiliations

  1. Applied Physics Graduate Program, Northwestern University, Evanston, IL, USA

    Xiaolong Liu & Mark C. Hersam

  2. Department of Materials Science and NanoEngineering, Rice University, Houston, TX, USA

    Zhuhua Zhang, Luqing Wang & Boris I. Yakobson

  3. State Key Laboratory of Mechanics and Control of Mechanical Structures and Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing, China

    Zhuhua Zhang

  4. Department of Chemistry, Rice University, Houston, TX, USA

    Boris I. Yakobson

  5. Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA

    Mark C. Hersam

  6. Department of Chemistry, Northwestern University, Evanston, IL, USA

    Mark C. Hersam

  7. Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, USA

    Mark C. Hersam

Authors
  1. Xiaolong Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Zhuhua Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Luqing Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Boris I. Yakobson
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Mark C. Hersam
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

X.L. and M.C.H. conceived the experiments. X.L. performed the sample preparation, STM/STS and XPS characterization. Z.Z., L.W. and B.I.Y. designed the models. Z.Z. and L.W. performed the DFT simulations. X.L. provided assistance with the model construction. All the authors contributed to the data interpretation and manuscript writing.

Corresponding author

Correspondence to Mark C. Hersam.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figures 1–11, Supplementary Table 1 and Supplementary Note 1

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Liu, X., Zhang, Z., Wang, L. et al. Intermixing and periodic self-assembly of borophene line defects. Nature Mater 17, 783–788 (2018). https://doi.org/10.1038/s41563-018-0134-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41563-018-0134-1

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing