Shuyun Zhou, Department of Physics, Tsinghua University

"Manipulation of two-dimensional materials by time-periodic light field"

Abstract: Time-periodic light-field can dress the electronic states of quantum materials, providing a fascinating controlling knob for transient modifications of the electronic structure with light-induced emergent phenomena [1]. In this talk, I will present our recent experimental progress on the Floquet engineering of a model semiconductor – black phosphorus. Time- and angle-resolved photoemission spectroscopy (TrARPES) measurements with mid-infrared pumping reveal the light-induced manipulation of the transient electronic structure with pseudospin selectivity, both upon near-resonance pumping [2] and far below-gap pumping [3]. In both cases, a strong modification of the transient electronic structure is clearly revealed near the top of the valence band, yet with distinctive behaviors. The implications of these results and insights for extending Floquet engineering to more materials will also be discussed.

[1] Changhua Bao et al., “Light-induced emergent phenomena in two-dimensional materials and topological materials”, Nat. Rev. Phys. 4, 33 (2022)

[2] Shaohua Zhou+, Changhua Bao+ et al., “Pseudospin-selective Floquet band engineering in black phosphorus”, Nature 614, 75 (2023)

[3] Shaohua Zhou+, Changhua Bao+, et al., “Floquet engineering of black phosphorus by below-gap pumping”, Phys. Rev. Lett. 131, 116401 (2023)