Ratchet effect in spatially modulated bilayer graphene: Signature of hydrodynamic transport
Erwin Mönch, S. O. Potashin, K. Lindner, I. Yahniuk, L. E. Golub, V. Yu. Kachorovskii, V. V. Bel’kov, Robin Huber, Kenji Watanabe, Takashi Taniguchi, Jonathan Eroms, D. Weiß, Sergey Ganichev
Abstract
The authors study here the transition between drift-diffusion and hydrodynamic regimes of ac electron transport in bilayer graphene, focusing on one of the most general photovoltaic phenomenon: the ratchet effect. Compared to conventional dc transport measurements, this effect offers a number of additional possibilities to probe hydrodynamic flow of the electron fluid. A signature of the hydrodynamic regime --- a very sharp frequency dependence of the generated ratchet current --- is clearly demonstrated experimentally, in excellent agreement with the developed theory.