Light-induced renormalization of the band structure of chiral tellurium

Chirality in tellurium arises from a Peierls distortion driven by strong electron-phonon coupling, making this material a unique candidate for observing a light-induced topological phase transition. Using time- and angle-resolved photoelectron spectroscopy (trARPES), we reveal that, upon near-infrared photoexcitation, the Peierls gap is modulated by displacively excited coherent phonons with A1g symmetry as well as chiral-symmetry-breaking ELO′ modes. By comparison with state-of-the-art TDDFT+U calculations, we reveal the microscopic origin of the in-phase oscillations of band edges, owing to phonon-induced modulation of the effective Hubbard U term.