It is known that, under the presence of a static external magnetic field $B_e$, an electromagnetic field rotates its polarization axes (Faraday rotation) when transmitted across a graphene single layer. Graphene provides record values of Faraday angle per layer thickness, but at frequencies of the order of the cyclotron frequency. This impedes applications, as fields of the order of 10 T would be required even for terahertz operation. Here we show that this condition is relaxed in strained graphene, where the potentially large induced pseudomagnetic field $B_{\text{ps}}$, when combined with a small $B_e$ (needed to break time-reversal symmetry), provides large Faraday rotation at arbitrary frequencies. It is found that the Faraday rotation in this system presents a very rich dependence on all different parameters, being greatly enhanced when the number of occupied Landau levels (governed by $B_e\pm B_{\text{ps}}$) is different in the two graphene valleys.

• Received 15 July 2019
• Revised 12 September 2019

DOI:https://doi.org/10.1103/PhysRevResearch.1.033049

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society