Electronic Steady States of Floquet Moiré Materials

Christopher Yang, California Institute of Technology

Photo of Christopher Yang

The electrical transport properties of periodically driven (e.g., laser-driven) materials can encode information about the drive-induced topology, electron-phonon interactions, and electron-electron interactions within the system1,2. In this work, we consider THz-laser driven twisted bilayer graphene (TBG) at low temperatures, whose optically induced topological bandstructure makes it possible to observe an effective anomalous quantum Hall effect in the system. We demonstrate that the laser drive flattens the effective bandstructure of TBG3, and the resulting anomalous transport properties behave differently in the weak drive and strong drive regimes when electrons are faster and slower than phonons, respectively. In both regimes, we show that interacting, Floquet TBG can avoid overheating by dissipating the laser drive energy to its low-temperature bath of phonons. Finally, we discuss how this work may generalize to UV light and X-ray driven Moiré materials.

1K. I. Seetharam, C. E. Bardyn, N. H. Linder, M. S. Rudner, and G. Refael, Steady states of interaction Floquet insulators, Physical Review B 99, 10.1103/PhysRevB.99.014307 (2019).
2N. H. Linder, G. Refael, and V. Galitski, Floquet topological insulator in semiconductor quantum wells, Nature Physics 7, 10.1038/nphys1926 (2011).
3O. Katz, G. Refael, and N. H. Linder, Optically induced flat bands in twisted bilayer graphene, Physical Review B 102, 10.1103/PhysRevB.102.155123 (2020).

Abstract Author(s): Christopher Yang, Iliya Esin, Cyprian Lewandowski, and Gil Refael