Nano Research

, Volume 11, Issue 11, pp 5946–5956 | Cite as

Superlubricity of epitaxial monolayer WS2 on graphene

  • Holger Büch
  • Antonio Rossi
  • Stiven Forti
  • Domenica Convertino
  • Valentina Tozzini
  • Camilla ColettiEmail author
Open Access
Research Article


We report the superlubric sliding of monolayer tungsten disulfide (WS2) on epitaxial graphene (EG) grown on silicon carbide (SiC). Single-crystalline WS2 flakes with lateral size of hundreds of nanometers are obtained via chemical vapor deposition (CVD) on EG. Microscopic and diffraction analyses indicate that the WS2/EG stack is predominantly aligned with zero azimuthal rotation. The present experiments show that, when perturbed by a scanning probe microscopy (SPM) tip, the WS2 flakes are prone to slide over the graphene surfaces at room temperature. Atomistic force field-based molecular dynamics simulations indicate that, through local physical deformation of the WS2 flake, the scanning tip releases enough energy to the flake to overcome the motion activation barrier and trigger an ultralow-friction rototranslational displacement, that is superlubric. Experimental observations show that, after sliding, the WS2 flakes come to rest with a rotation of nπ/3 with respect to graphene. Moreover, atomically resolved measurements show that the interface is atomically sharp and the WS2 lattice is strain-free. These results help to shed light on nanotribological phenomena in van der Waals (vdW) heterostacks, and suggest that the applicative potential of the WS2/graphene heterostructure can be extended by novel mechanical prospects.


superlubricity graphene tungsten disulfide scanning tunneling microscopy (STM) two-dimensional (2D) materials nanomechanical 



We wish to thank Professor Annalisa Fasolino for useful discussions and suggestions. The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement Nos. 696656 – GrapheneCore1 and 785219 – GrapheneCore2.

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Superlubricity of epitaxial monolayer WS2 on graphene


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© The Author(s) 2018
, corrected publication 08/2018

Open Access: This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

Authors and Affiliations

  • Holger Büch
    • 1
  • Antonio Rossi
    • 1
    • 2
  • Stiven Forti
    • 1
  • Domenica Convertino
    • 1
    • 2
  • Valentina Tozzini
    • 2
  • Camilla Coletti
    • 1
    • 3
    Email author
  1. 1.Center for Nanotechnology Innovation @NESTIstituto Italiano di TecnologiaPisaItaly
  2. 2.NEST, Istituto Nanoscienze – CNR and Scuola Normale SuperiorePisaItaly
  3. 3.Graphene LabsIstituto Italiano di TecnologiaGenovaItaly

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