Mahmood, Fahad; Chan, Ching; Alpichshev, ZhanybekISTA ; Gardner, Dillon; Lee, Young; Lee, Patrick; Gedik, Nuh
The coherent optical manipulation of solids is emerging as a promising way to engineer novel quantum states of matter. The strong time-periodic potential of intense laser light can be used to generate hybrid photon-electron states. Interaction of light with Bloch states leads to Floquet-Bloch states, which are essential in realizing new photo-induced quantum phases. Similarly, dressing of free-electron states near the surface of a solid generates Volkov states, which are used to study nonlinear optics in atoms and semiconductors. The interaction of these two dynamic states with each other remains an open experimental problem. Here we use time- and angle-resolved photoemission spectroscopy (Tr-ARPES) to selectively study the transition between these two states on the surface of the topological insulator Bi2Se3. We find that the coupling between the two strongly depends on the electron momentum, providing a route to enhance or inhibit it. Moreover, by controlling the light polarization we can negate Volkov states to generate pure Floquet-Bloch states. This work establishes a systematic path for the coherent manipulation of solids via light-matter interaction.
The authors would like to thank C. Lee for useful discussions. This work is supported by US Department of Energy (DOE), Basic Energy Sciences, Division of Materials Sciences and Engineering (experimental set-up, data acquisition and theory), Army Research Office (electron spectrometer) and by the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant GBMF4540 (data analysis).
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Mahmood F, Chan C, Alpichshev Z, et al. Selective scattering between Floquet Bloch and Volkov states in a topological insulator. Nature Physics. 2016;12(4):306-310. doi:10.1038/nphys3609
Mahmood, F., Chan, C., Alpichshev, Z., Gardner, D., Lee, Y., Lee, P., & Gedik, N. (2016). Selective scattering between Floquet Bloch and Volkov states in a topological insulator. Nature Physics. Nature Publishing Group. https://doi.org/10.1038/nphys3609
Mahmood, Fahad, Ching Chan, Zhanybek Alpichshev, Dillon Gardner, Young Lee, Patrick Lee, and Nuh Gedik. “Selective Scattering between Floquet Bloch and Volkov States in a Topological Insulator.” Nature Physics. Nature Publishing Group, 2016. https://doi.org/10.1038/nphys3609.
F. Mahmood et al., “Selective scattering between Floquet Bloch and Volkov states in a topological insulator,” Nature Physics, vol. 12, no. 4. Nature Publishing Group, pp. 306–310, 2016.
Mahmood F, Chan C, Alpichshev Z, Gardner D, Lee Y, Lee P, Gedik N. 2016. Selective scattering between Floquet Bloch and Volkov states in a topological insulator. Nature Physics. 12(4), 306–310.
Mahmood, Fahad, et al. “Selective Scattering between Floquet Bloch and Volkov States in a Topological Insulator.” Nature Physics, vol. 12, no. 4, Nature Publishing Group, 2016, pp. 306–10, doi:10.1038/nphys3609.