Light-Induced Floquet Effects in Graphene under Continuous-Wave Mid-Infrared Irradiation

Light-matter interaction in 2D materials is predicted to induce Floquet-Bloch states with non-trivial topology [1,2,3]. We report on the experimental observation of photoinduced transverse voltage and photoinduced current in graphene Hall bars irradiated with high-power linearly and circularly-polarized mid-Infrared radiation at cryogenic temperatures. The radiation wavelength is 10.6 μm and the power density is larger than 1 mW/μm². We investigate the dependence of the photoresponse on the temperature, position of Fermi level, and light polarization. The observation of Floquet signatures at lower power densities and in the CW regime lifts substantial experimental restrictions, helping to unlock potential applications for light-induced manipulation of material properties [4].<br/>We acknowledge support from NSF (projects DMR CMP #2104755 and DMR CMP #2104770). The National High Magnetic Field Laboratory is supported by the National Science Foundation through NSF/DMR-2128556 and the State of Florida.<br/>References:<br/>[1] T. Oka, H. Aoki, Phys. Rev. B 79, 081406(R) (2009).<br/>[2] H. Calvo et al., Appl. Phys. Lett. 98, 232103 (2011); L. E. F. Foa Torres et al. Phys. Rev. Lett. 113, 266801 (2014).<br/>[3] J. McIver et al., Nat. Phys. 16, 38 (2020).<br/>[4]. Y.Liu et.al. APS March Meeting 2023, A32.00007