Sub-cycle controlled electron dynamics in graphene

This talk presents recent results on coherently controlled electron dynamics in quantum materials [1], focusing on light-field driven interferometry [2,3] and Floquet engineering [4]. This control is achieved by coupling waveform-optimized laser pulses with graphene’s unique band structure, allowing for band structure retrieval and probing of electronic coherence [5] with high temporal precision. Leveraging Floquet engineering, we also induce novel transient states, turning graphene into a Floquet topological insulator (FTI), revealing pathways to dynamically tailor graphene’s electronic properties [4]. This includes all-optical anomalous Hall photocurrents, valley-polarized currents, and photocurrent circular dichroism, all phenomena that put FTIs on equal footing with equilibrium topological insulators. Our results showcase how sub-cycle electron control and interferometry in graphene open new avenues for applications in ultrafast electronics [3] and real-time materials characterization [1,2].

[1] Heide, C. et al., Ultrafast high-harmonic spectroscopy of solids. Nature Physics (2024).

[2] Weitz, T. et al., Strong-Field Bloch Electron Interferometry for Band Structure Retrieval. Phys Rev Lett 132, 206901 (2023).

[3] Heide, C. et al., Petahertz Electronics. Nature Review Physics (2024).

[4] Weitz, T. et al., Lightwave-driven electrons in a Floquet topological insulator arXiv:2407.17917 (2024)

[5] Heide C. et al., Electronic coherence and coherent dephasing in the optical control of electrons in graphene, Nano Letters 21, 9403 (2021)