Abstract
Friction between two ideal single crystals is expected to be very small if there is an incommensurate orientational mis-setting θ between the crystals (provided that the interlayer couplings are small). We consider here a different case: two identical monolayers (of materials such as MoS 2 or graphite) in ideal conditions (high purity; high vacuum; no dislocations in both layers). Two dimensional crystals have anomalous fluctuations, analyzed long ago by B. Jancovici. The Bragg reflections are not sharp, but diffuse. The X-ray (or neutron) scattering near the nominal Bragg peaks is singular, and dominated by multiphonon processes. Incorporating this form of dynamics, we construct a scaling prediction for the viscous friction stress expected at slow relative velocities V. It is predicted to be very large! This conclusion would also hold for one monolayer facing a bulk crystal. Our discussion is qualitative (ignoring all numerical coefficients) but relatively simple. To cite this article: P.-G. de Gennes, C. R. Physique 7 (2006).
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
