THz Phonon Generation in Graphene Driven Out of Equilibrium

POSTER

Abstract

In ultraclean graphene devices driven out of equilibrium, electrons can reach high drift velocities with relative ease. When the drift velocity of electrons exceeds the speed of sound in a material, stimulated phonon emission dominates over absorption. This can result in an amplification of THz frequency phonons in the direction of carrier flow. We explore the local electrical properties along long graphene devices, observing a 7-fold increase in resistivity over a distance of 8 microns. Phonon amplification is demonstrated under a wide range of carrier densities (0.5 to 4*10^12 cm^-2) and temperatures (1.5 to 280K). The resulting inhomogeneous resistivity could modify electron transport measurements in similar devices and act as another effect for consideration for long graphene devices. Our findings suggest future applications as a novel on-chip THz phonon generator, which could be coupled to other 2D materials to modify crystal structure on the order of the atomic lattice.

Presenters

  • Jasen Zion

    • Caltech

Authors

  • Jasen Zion

    • Caltech

  • Aaron H Barajas Aguilar

    • University of California, Irvine

  • Ian Sequeira

    • University of California, Irvine

  • Andrew Barabas

    • University of California, Irvine

  • Kenji Watanabe

    • National Institute for Materials Science
    • Research Center for Functional Materials, National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Takashi Taniguchi

    • National Institute for Materials Science
    • Kyoto Univ
    • International Center for Materials Nanoarchitectonics, National Institute of Materials Science
    • Kyoto University
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institute For Materials Science
    • NIMS
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Javier D Sanchez-Yamagishi

    • University of California, Irvine