Research paperTheoreticalValley separation of photoexcited carriers in bilayer grapheneT. J. Osborne, M. E. Portnoi, E. Mariani2026·10.48550/arxiv.2409.08807·arXiv:2409.08807AbstractWe derive the angular generation density of photoexcited carriers in gapless and gapped Bernal bilayer graphene. Using the strong low-energy anisotropy from trigonal warping, we show that carriers in different valleys can propagate to different sides of a light spot after photoexcitation, with inter-valley electron-phonon scattering suppressed in the low-energy regime. We further show that momentum alignment with linearly polarized light can enhance this valley polarization, and that gapped bilayer graphene exhibits valley-dependent optical selection rules for circularly polarized light. The work predicts an optical valley Hall effect and proposes realistic experimental setups for gapless and gapped bilayer graphene devices operating in the terahertz regime.Read more
Research paperTheoreticalValley separation of photoexcited carriers in bilayer grapheneT. J. Osborne, M. E. Portnoi, E. Mariani2026·10.48550/arxiv.2409.08807·arXiv:2409.08807AbstractWe derive the angular generation density of photoexcited carriers in gapless and gapped Bernal bilayer graphene. Using the strong low-energy anisotropy from trigonal warping, we show that carriers in different valleys can propagate to different sides of a light spot after photoexcitation, with inter-valley electron-phonon scattering suppressed in the low-energy regime. We further show that momentum alignment with linearly polarized light can enhance this valley polarization, and that gapped bilayer graphene exhibits valley-dependent optical selection rules for circularly polarized light. The work predicts an optical valley Hall effect and proposes realistic experimental setups for gapless and gapped bilayer graphene devices operating in the terahertz regime.Read more
Research paperTheoreticalValley separation of photoexcited carriers in bilayer grapheneT. J. Osborne, M. E. Portnoi, E. Mariani2026·10.48550/arxiv.2409.08807·arXiv:2409.08807AbstractWe derive the angular generation density of photoexcited carriers in gapless and gapped Bernal bilayer graphene. Using the strong low-energy anisotropy from trigonal warping, we show that carriers in different valleys can propagate to different sides of a light spot after photoexcitation, with inter-valley electron-phonon scattering suppressed in the low-energy regime. We further show that momentum alignment with linearly polarized light can enhance this valley polarization, and that gapped bilayer graphene exhibits valley-dependent optical selection rules for circularly polarized light. The work predicts an optical valley Hall effect and proposes realistic experimental setups for gapless and gapped bilayer graphene devices operating in the terahertz regime.Read more
Research paperTheoreticalValley separation of photoexcited carriers in bilayer grapheneT. J. Osborne, M. E. Portnoi, E. Mariani2026·10.48550/arxiv.2409.08807·arXiv:2409.08807AbstractWe derive the angular generation density of photoexcited carriers in gapless and gapped Bernal bilayer graphene. Using the strong low-energy anisotropy from trigonal warping, we show that carriers in different valleys can propagate to different sides of a light spot after photoexcitation, with inter-valley electron-phonon scattering suppressed in the low-energy regime. We further show that momentum alignment with linearly polarized light can enhance this valley polarization, and that gapped bilayer graphene exhibits valley-dependent optical selection rules for circularly polarized light. The work predicts an optical valley Hall effect and proposes realistic experimental setups for gapless and gapped bilayer graphene devices operating in the terahertz regime.Read more
