Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 8: Ultrafast Phenomena I

HL 8.11: Talk

Monday, March 18, 2024, 17:45–18:00, EW 015

Harmonic generation with topological edge states and electron-electron interaction — •Siamak Pooyan and Dieter Bauer — Institute of Physics, Rostock University, 18051 Rostock, Germany

It has been found previously that the presence or absence of topological edge states in the Su-Schrieffer-Heeger (SSH) model in its toplogical and trivial phase, respectively, has a huge impact on harmonic generation spectra. More specifically, the yield of harmonics for harmonic orders that correspond to photon energies below the band gap is many orders of magnitude different in the trivial and topological phase. It is shown in this work that this effect is still present if nearest-neighbor electron-electron interaction is taken into account, i.e., if a Hubbard term is added to the SSH Hamiltonian. To that end, finite SSH-Hubbard chains at half filling are considered that are short enough to be accessible to exact diagonalization but already showing edge states in the topological phase. We show that the huge difference in the harmonic yield between trivial and topological phase can be reproduced with few-level models employing only the many-body ground state and a few excited many-body states in the trivial and topological phase, respectively.

Keywords: High-harmonic generation; Su-Schrieffer-Heeger; Hubbard; Strong laser fields; Topological edge states