- Open Access
Time-resolved ARPES in pumped excitonic systems: Floquet physics induced by excitonic fields
Phys. Rev. B 114, 194304 – Published 16 October, 2026
DOI: https://doi.org/10.1103/18mz-pmgh
Abstract
We develop a theoretical framework based on the dynamical projective operatorial approach (DPOA) to study the time-resolved and angle-resolved photoemission spectroscopy (TR-ARPES) of pumped excitonic systems. Including Coulomb electron-electron interactions at the Hartree-Fock level, our formalism captures the formation of excitonic bound states under the application of pump pulses. Considering a prototypical two-dimensional two-band semiconductor, we analyze the equilibrium phase diagram, which shows the expected transition from a semiconducting to an excitonic-insulator phase as the Coulomb interaction strength or its range increases. Out of equilibrium, we find that when the pump frequency is resonant with an excitonic mode, coherent oscillations of the excitonic order parameter persist after the pump pulse subsides, and they give rise to clear Floquet sidebands in the TR-ARPES spectrum. These exciton-field-induced sidebands are distinct from those originating from the pump laser field. We also identify band-resonance-induced sidebands arising from residual coherences at momenta where the band gap is resonant with the pump frequency. Finally, we analyze the local Coulomb interaction limit. Our results corroborate recent experimental observations of exciton-field-induced Floquet-like sidebands and establish DPOA as an efficient and accurate method for simulating ultrafast phenomena in interacting electron systems.
Physics Subject Headings (PhySH)
- Excited-state quantum phase transitions
- Excitons
- Ultrafast phenomena
- Excitonic insulators
- Bloch-Floquet theorem
- Hartree-Fock methods
- Nonequilibrium Green's function
- Second quantization
- Tight-binding model
- Time & angle resolved photoemission spectroscopy
- Ultrafast femtosecond pump probe
- Ultrafast pump-probe spectroscopy
- Wannier function methods
Article Text
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