TY - JOUR T1 - Chiral transport of hot carriers in graphene in the quantum Hall regime Y1 - 2021 A1 - Bin Cao A1 - Tobias Grass A1 - Olivier Gazzano A1 - Kishan Ashokbhai Patel A1 - Jiuning Hu A1 - Markus Müller A1 - Tobias Huber A1 - Luca Anzi A1 - Kenji Watanabe A1 - Takashi Taniguchi A1 - David Newell A1 - Michael Gullans A1 - Roman Sordan A1 - Mohammad Hafezi A1 - Glenn Solomon AB -

Photocurrent (PC) measurements can reveal the relaxation dynamics of photo-excited hot carriers beyond the linear response of conventional transport experiments, a regime important for carrier multiplication. In graphene subject to a magnetic field, PC measurements are able to probe the existence of Landau levels with different edge chiralities which is exclusive to relativistic electron systems. Here, we report the accurate measurement of PC in graphene in the quantum Hall regime. Prominent PC oscillations as a function of gate voltage on samples' edges are observed. These oscillation amplitudes form an envelope which depends on the strength of the magnetic field, as does the PCs' power dependence and their saturation behavior. We explain these experimental observations through a model using optical Bloch equations, incorporating relaxations through acoustic-, optical- phonons and Coulomb interactions. The simulated PC agrees with our experimental results, leading to a unified understanding of the chiral PC in graphene at various magnetic field strengths, and providing hints for the occurrence of a sizable carrier multiplication. 

UR - https://arxiv.org/abs/2110.01079 ER -