Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Poster Monday: 2D Materials 1

O 18.18: Poster

Montag, 5. September 2022, 18:00–20:00, P4

Resonant photoemission studies at the Fe 3p threshold on thin FeTe/Bi₂Te₃ and FeSe/Bi₂Se₃ — •Martin Vondráček¹, Tomáš Skála², Karel Carva², Gunther Springholz³, and Jan Honolka¹ — ¹Institute of Physics of the Czech Academy of Sciences, Prague, CZ — ²Charles University, Faculty of Mathematics and Physics, Prague, CZ — ³Johannes Kepler University, Institute of Semiconductor and Solid State Physics, Linz, AT

Monolayers (MLs) of tetragonal FeTe and FeSe grow on hexagonal Bi₂Se₃(111) and Bi₂Te₃(111) substrates as three 60^∘-rotated domains. In scanning tunnelling spectroscopy, a gap appears at the Fermi level of FeTe/Bi₂Te₃ suggesting interface-induced superconductivity below Tc ≈ 6 K [1]. FeSe/Bi₂Se₃ remains in a gapless state [2]. Unconventional superconductivity in Fe-chalcogenides (FeChs) is believed to be correlated to the texture of the Fermi surface at Γ- and M-points. However, ARPES data of FeCh MLs on Bi₂Ch₃ is complex due to the superposition of contributions from all three domains. Here we show photon energy dependent UPS data probing k_z dispersions along the Γ-Z direction. Fano-like modulations of valence band intensities are observed in the energy range 30-80 eV, indicative of a resonant photoemission effect at the Fe 3p edge around 55 eV. Our ML data is compared to previous bulk studies [3].

[1] A. Eich et al., Phys. Rev. B 94, 125437 (2016). [2] S. Manna et al., Nat. Commun. 8, 14074 (2017). [3] T. Yokoya et al., Sci. Technol. Adv. Mater. 13 (2012) 054403.