Condensed-matter physics Light tailors the electronic properties of a model semiconductor

Article Multidisciplinary Sciences

Pseudospin-selective Floquet band engineering in black phosphorus

Shaohua Zhou et al.

Summary: Time-periodic light field has been used to manipulate quantum states in solid-state materials, cold atoms, and photonic systems. This is achieved through interaction with photon-dressed Floquet states in the strong-coupling limit, known as Floquet engineering. In this study, experimental evidence of momentum-resolved Floquet band engineering in a model semiconductor, black phosphorus, is reported using time and angle-resolved photoemission spectroscopy measurements. Strong band renormalization and light-induced dynamical gap opening are observed near the band edges under near-resonance pumping, along with the emergence of Floquet sidebands. The band renormalization shows a selection rule favoring pump polarization along the armchair direction, indicating pseudospin selectivity for Floquet band engineering enforced by lattice symmetry. This work demonstrates pseudospin-selective Floquet band engineering in black phosphorus and provides important guiding principles for Floquet engineering of semiconductors.

NATURE (2023)

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Article Physics, Multidisciplinary