Discovery of Coulomb-Drag Instability of Graphene Dirac Plasmons

Quasi-ballistic electrons injected from the
$\mathrm{n}^{+}$
region into the gated n-region of the
$\mathrm{n}^{+}\text{-}\mathrm{i}\text{-}\mathrm{n}\text{-}\mathrm{n}^{+}$
graphene FET (GFET) strongly drag the quasi-equilibrium electrons in the n-region. We found that this Coulomb drag can substantially influence the current-voltage characteristics leading to instability of graphene Dirac plasmons and resulting in coherent oscillations/ amplification in the terahertz range.