Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 14: 2D Materials Beyond Graphene: Growth, Structure and Substrate Interaction (joint session O/HL)

O 14.5: Talk

Monday, March 17, 2025, 16:00–16:15, H11

Growth and Structure of Titanium Ditelluride Films on Au(111) — •Andreas Raabgrund, Alexander Wegerich, Lutz Hammer, and M. Alexander Schneider — Universität Erlangen-Nürnberg, 91058 Erlangen, Germany

Aiming at the MBE growth of transition metal ditelluride (MTe2) films particularly in the single-layer limit, the formation of and interaction with the interface is of fundamental interest. The growth of a MTe2 film can be achieved either by the tellurization of the desired metal substrate [1] or by the reactive deposition of Te and the corresponding transition metal M on a suitable substrate [2].

In this contribution we follow the latter approach and investigate both single- and multilayer TiTe2 films on Au(111) by LEED-IV, DFT, and STM. At first glance, LEED suggests a (4× 4) superstructure with three TiTe2 on four Au(111) unit cells. STM topography, however, reveals a mismatch of about 1% of the growing film w.r.t. the Au(111) substrate which indicates a relaxed TiTe2 layer. LEED-IV results favor a film in close contact with Au substrate (Te-Au layer distance: ≈2.7 Å). By DFT total energy calculations we find that neither Te nor Ti substitution is favored in the topmost Au layer. Continuing the reactive deposition of Ti and Te a multilayer TiTe2 film grows epitaxially as found by LEED-IV with a Pendry R factor of 0.12. Further, we discuss the transferability of this growth recipe to other MTe2 films on Au(111).
[1] T. Kißlinger et al., Phys. Rev. B 108, 205412 (2023)
[2] K. Lasek et al., ACS Nano 14, 8473 (2020)

Keywords: Titanium Tellurides; TMDC; Au(111); STM; LEED-IV