SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 67: Poster: Electronic Structure of Surfaces

O 67.5: Poster

Mittwoch, 29. März 2023, 18:00–20:00, P2/EG

Quasiparticle lifetime and formation of electronic states at Tellurium–metal interfaces — •Begmuhammet Geldiyev^1,3, Maximilian Ünzelmann^1,3, Philipp Eck^2,3, Domenico Di Sante^2,3, Giorgio Sangiovanni^2,3, Thomas Fauster⁴, Hendrik Bentmann^1,3, and Friedrich Reinert^1,3 — ¹Experimentelle Physik 7, Universität Würzburg — ²Theoretische Physik 1, Universität Würzburg — ³Würzburg-Dresden Cluster of Excellence ct.qmat — ⁴Lst. f. Festkörperphysik, Universität Erlangen-Nürnberg

Properties of interfaces between a device material and metallic contacts can decisively influence the resulting device performance. In particular, the formation of electronic interface states (IS) with short lifetimes could speed up the charge carrier injection [1]. In this contribution, we will discuss the formation of IS at Te – noble metal interfaces, i.e., particularly in a suitable model system AgTe / Ag(111) [2]. Utilizing one- and two-photon photoemission, we find that hybridizations between Te-p_z orbitals with substrate bulk and surface states determine the interface electronic structure. Whilst the AgTe valence band states are located almost completely within the AgTe layer, the wave function of the unoccupied state γ, lying 530 meV above E_F within the projected bulk band gap, has a sizable overlap with the substrate states. Evidence is provided by a rather short lifetime τ = 31 ± 3 fs of γ as well as by light-polarization-dependent measurements revealing the orbital character of the occupied and unoccupied states.

[1] C. H. Schwalb et al., Phys. Rev. Lett. 101, 146801 (2008)

[2] M. Ünzelmann et al., Phys. Rev. Lett. 124, 176401 (2020)