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O: Fachverband Oberflächenphysik

O 67: Focus Session: Unoccupied States by Inverse Photoemission II

O 67.6: Vortrag

Mittwoch, 11. März 2026, 16:30–16:45, WILL/A317

Modeling a transient Dirac-like surface state in Floquet-driven SnTe — •Aki Pulkkinen¹, Frédéric Chassot², Hugo Dil³, Claude Monney², and Ján Minár¹ — ¹New Technologies-Research Centre, University of West Bohemia in Pilsen, Czechia — ²Department of Physics and Fribourg Center for Nanomaterials, Université de Fribourg, Switzerland — ³Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, Switzerland

We present a theoretical analysis of the ultrafast transient cone-like dispersion observed in pump-probe photoemission experiments on SnTe[1]. A semi-infinite (111) surface Hamiltonian is constructed from a Wannier tight-binding model, and the surface Green's function is obtained using the recursive López-Sancho method[2] in extended Hilbert space. The effect of the pump pulse is introduced through a time-periodic Peierls substitution and a Jacobi-Anger expansion of the driven Hamiltonian into Floquet sectors. The Floquet-Green's-function calculations show that photoexcitation induces a transient hybridization between the Floquet replica of the valence band and the conduction band, producing a momentary band inversion at the surface. The inversion generates a short-lived Dirac-cone-like surface state, reproducing the main experimental feature. The results indicate that the transient cone originates from Floquet-induced reconstruction rather than structural or thermal effects, and demonstrate the role of strong periodic driving in reshaping surface electronic structure in SnTe. [1] F Chassot et al. 2025 arXiv:2502.11967 [2] M. P. Lopez Sancho et al. 1985 J. Phys. F: Met. Phys. 15 851

Keywords: Floquet engineering; Surface Green’s function; SnTe (111); Transient surface states; Wannier tight binding