Observation of chiral photocurrent transport in the quantum Hall regime in graphene

Published

May 24, 2021

Author(s)

Glenn S. Solomon, Olivier Gazzano, Bin Cao, Jiuning Hu, David B. Newell, Tobias Huber, Michael Gullans, Mohammad Hafezi, Tobias Grass

Abstract

Optical excitation provides a powerful tool to investigate non-equilibrium physics in quantum Hall systems. Moreover, the length scale associated with photo-excited charge carries lies between that of local probes and global transport measurements. Here, we investigate non-equilibrium physics of optically-excited charge carriers in graphene through photocurrent measurements in the integer quantum Hall regime. We observe that the photocurrent oscillates as a function of Fermi level, revealing the Landau-level quantization, and that the photocurrent oscillations are different for Fermi levels near and distant from the Dirac point. Our observation qualitatively agrees with a model that assumes the photocurrent is dominated by chiral edge transport of non-equilibrium carriers. Our experimental results are consistent with electron and hole chiralities being the same when the Fermi level is distant from the Dirac point, and opposite when near the Dirac point.

Citation

arXiv

Pub Type

Journals

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Keywords

graphene, Integer quantum Hall, photocurrent

Citation

Solomon, G. , Gazzano, O. , Cao, B. , Hu, J. , Newell, D. , Huber, T. , Gullans, M. , Hafezi, M. and Grass, T. (2021), Observation of chiral photocurrent transport in the quantum Hall regime in graphene, arXiv, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=927981 (Accessed April 19, 2024)