1206.2940 (I. Petkovic et al.)

Chiral magneto-plasmons on the quantum Hall edge in graphene    [PDF]

I. Petkovic, F. I. B. Williams, K. Bennaceur, F. Portier, P. Roche, D. C. Glattli

Edges and chirality are elements vital to the quantum Hall effect. It is at the edge that charge accumulates and chiral currents flow without scattering. But edges also host collective excitations in the form of chiral, globally neutral Edge Magneto-Plasmons (EMP). Much investigated in conventional 2-dimensional electron systems, little is known about them in the newly discovered graphene system where electrons obey massless relativistic dynamics. Here, by timing the propagation of narrow wave-packets on picosecond time scales, we show experimentally the chirality and quantization of the velocity of EMP modes on the Hall plateaus. The measurements also allow us to estimate the drift velocity of carriers along the edge. It is expected to be of the order of the Fermi velocity, which in graphene is particularly high. Edge magneto-plasmons in graphene should survive at room temperature, opening the way to using them to make fast chiral devices.

View original: http://arxiv.org/abs/1206.2940