Load-induced dynamical transitions at graphene interfaces

Deli Peng, Zhanghui Wu, Diwei Shi, Cangyu Qu, Haiyang Jiang, Yiming Song, Ming Ma, Gabriel Aeppli, Michael Urbakh, Quanshui Zheng

Research output: Contribution to journalArticlepeer-review

Abstract

The structural superlubricity (SSL), a state of near-zero friction between two contacted solid surfaces, has been attracting rapidly increasing research interest since it was realized in microscale graphite in 2012. An obvious question concerns the implications of SSL for micro- and nanoscale devices such as actuators. The simplest actuators are based on the application of a normal load; here we show that this leads to remarkable dynamical phenomena in microscale graphite mesas. Under an increasing normal load, we observe mechanical instabilities leading to dynamical states, the first where the loaded mesa suddenly ejects a thin flake and the second characterized by peculiar oscillations, during which a flake repeatedly pops out of the mesa and retracts back. The measured ejection speeds are extraordinarily high (maximum of 294 m/s), and correspond to ultrahigh accelerations (maximum of 1.1×1010 m/s2). These observations are rationalized using a simple model, which takes into account SSL of graphite contacts and sample microstructure and considers a competition between the elastic and interfacial energies that defines the dynamical phase diagram of the system. Analyzing the observed flake ejection and oscillations, we conclude that our system exhibits a high speed in SSL, a low friction coefficient of 3.6×10−6, and a high quality factor of 1.3×107 compared with what has been reported in literature. Our experimental discoveries and theoretical findings suggest a route for development of SSL-based devices such as high-frequency oscillators with ultrahigh quality factors and optomechanical switches, where retractable or oscillating mirrors are required.

Original languageEnglish
Pages (from-to)12618-12623
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number23
DOIs
StatePublished - 9 Jun 2020

Keywords

  • Dynamic transitions speed
  • Graphene/graphite
  • High
  • Oscillation
  • Structural superlubricity

Fingerprint

Dive into the research topics of 'Load-induced dynamical transitions at graphene interfaces'. Together they form a unique fingerprint.

Cite this