Massive thermal fluctuation of massless graphene electrons

Abstract

Whereas thermal current noise $⟨I^2⟩$ in typical conductors is proportional to temperature $T$, $⟨I^2⟩$ in graphene exhibits a nonlinear $T$ dependence due to the massless nature of individual electrons. This unique $⟨I^2⟩$ arising from individually massless electrons is intimately linked to the non-zero collective mass of graphene electrons; namely, $⟨I^2⟩$ is set by the equipartition theorem applied to the collective mass's kinetic energy, with the nonlinear $T$-dependence arising from the $T$-dependence of the collective mass. This link between thermal fluctuation and collective dynamics unifies $⟨I^2⟩$ in graphene and typical conductors, while elucidating the uniqueness of the former at the same time.

5 pages, 3 figures