Dresden 2026 – scientific programme

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O: Fachverband Oberflächenphysik

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

O 67.11: Talk

Wednesday, March 11, 2026, 17:45–18:00, WILL/A317

2D IPES intensity maps of MoS₂ — •Patricia Martínez-Rojas, Sanber Vizcaya, Rolando Esparza, and Patricio Häberle — Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso, Chile

Inverse photoemission spectroscopy (IPES) offers direct access to the unoccupied electronic structure of solids and is particularly well suited for investigating layered transition-metal dichalcogenides such as MoS₂. We present momentum-resolved IPES measurements on a bulk 2H-MoS₂ single crystal, performed with a normal-incidence grating spectrometer operated at a fixed electron kinetic energy of 25.6 eV. The sample was prepared by ex-situ exfoliation and subsequently annealed, in UHV, up to 400^∘C to remove surface contaminants. By recording the photon intensity as a function of emission energy and incidence angle, we constructed two-dimensional maps of the unoccupied states along the ΓK and ΓM directions of the Brillouin zone. The data reveal several dispersive features whose energy-momentum dependence closely matches density-functional theory (DFT) band-structure calculations. In particular, the conduction-band minimum is experimentally found away from high-symmetry points, consistent with theoretical predictions. These results highlight the capability of momentum-resolved IPES to characterize the unoccupied band structure of MoS₂ and provide a benchmark for future studies of two-dimensional materials.

Keywords: Inverse Photoemission Spectroscopy; unoccupied electronic states; molybdenum disulfide; transition-metal dichalcogenides; band structure