• 文献标题:   Electron-phonon instability in graphene revealed by global and local noise probes
  • 文献类型:   Article
  • 作  者:   ANDERSEN TI, DWYER BL, SANCHEZYAMAGISHI JD, RODRIGUEZNIEVA JF, AGARWAL K, WATANABE K, TANIGUCHI T, DEMLER EA, KIM P, PARK H, LUKIN MD
  • 作者关键词:  
  • 出版物名称:   SCIENCE
  • ISSN:   0036-8075 EI 1095-9203
  • 通讯作者地址:   Harvard Univ
  • 被引频次:   12
  • DOI:   10.1126/science.aaw2104
  • 出版年:   2019

▎ 摘  要

Understanding and controlling nonequilibrium electronic phenomena is an outstanding challenge in science and engineering. By electrically driving ultraclean graphene devices out of equilibrium, we observe an instability that is manifested as substantially enhanced current fluctuations and suppressed conductivity at microwave frequencies. Spatial mapping of the nonequilibrium current fluctuations using nanoscale magnetic field sensors reveals that the fluctuations grow exponentially along the direction of carrier flow. Our observations, including the dependence on density and temperature, are consistently explained by the emergence of an electron-phonon Cerenkov instability at supersonic drift velocities. These results offer the opportunity for tunable terahertz generation and active phononic devices based on two-dimensional materials.