Thursday, April 30, 2026
4:00 pm-5:00 pm
Towards steady-state Floquet engineering in graphenes
Light-matter interaction can induce Floquet-Bloch states which may also have non-trivial topology [1–4]. Such Floquet engineering in graphene has been predominantly explored using ultra-fast techniques studying transient dynamics. We use different approach: we do transport measurements of graphene irradiated by a continuous-wave (CW) mid-infrared laser radiation [5]. In epitaxial graphene on SiC, we observed photoresponse signatures of a long-lived Floquet phase, where a non-equilibrium electronic population is stabilized by the interplay of coherent photoexcitation and incoherent cooling via phonon scattering [6]. Our results pave the way to investigations of steady Floquet physics in other types of graphene devices and substrates. One of other types of samples is the twisted bilayer graphene, where the capability to control band structure by varying the twist angle in moiré lattice opens up a new way to explore light-matter interactions [7,8]. The occurrence of flat bands in magic-angle twisted bilayer graphene (MATBLG) enables creation of devices with transport features which can be revealed from their contributions to the photoresponse [9-12]. Recently, we measured the dependence of the mid-infrared photoresponse in MATBLG on gate voltage, while varying light intensity, polarization, and magnetic field, to unveil the complexity of the interplay between light and magnetic field in these systems.
We acknowledge support from NSF (projects DMR CMP #2104755, DMR CMP #2104770, and OSI #2329006), The National High Magnetic Field Laboratory (NHMFL) is supported by the National Science Foundation through NSF/DMR-1644779, NSF/DMR-2128556 and the State of Florida.
References
[1] T. Oka, S. Kitamura, Annual Review of Condensed Matter Physics, 10 (2019) 387-408.
[2] M.S. Rudner, N.H. Lindner, Nature Reviews Physics, 2 (2020) 229-244.
[3] Y.H. Wang, et.al. Nature Physics, 16 (2020) 38–41.
[4] T. Oka, H. Aoki, Physical Review B, 79 (2009) 081406.
[5] Y. Liu, et.al. Small Methods 10, no. 3 (2026): e01482
[6] Y. Liu, et.al., Nature Communications, 16 (2025) 2057.
[7] Yantao Li, et.al. Physical Review Research 2, 043275 (2020).
[8] Topp, G. E., et.al.. Physical Review Research, 1(2), 023031
[9] Hubmann, S., et.al. 2D Materials, 10(2), 025002 (2023)
[10] Hubmann, S., et.al. Physical Review Materials, 6(2), 024003 (2022) [11] Kumar et al, Nature Materials volume 24, page 978 (2025)
[12] E.Persky et al, arXiv:2503.21750v1
