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O: Fachverband Oberflächenphysik

O 39: 2D Materials III: Growth and Heterostructures (joint session O/HL)

O 39.10: Vortrag

Dienstag, 17. März 2020, 12:45–13:00, GER 38

Two-dimensional metal phases and non-stoichiometric phases of transition metal dichalcogenides — •Thomas Joseph, Mahdi Ghorbani-Asl, and Arkady Krasheninnikov — Helmholtz-Zentrum Dresden Rossendorf, Bautzner Landstraße 400, Dresden

Changing the stoichiometry of a material in a controllable manner is a powerful tool to tailor the structure and the properties of a compound solid. For example, new morphologies, such as inversion domains with the associated mirror twin boundaries [1] can be produced in 2D transition metal dichaclogenides by sputtering chalcogen atoms using electron beam [1]. Moreover, suspended monolayer Mo membranes were recently fabricated from monolayer MoSe₂ sheets via complete sputtering of Se atoms in a scanning transmission electron microscope [2]. Motivated by these results, we performed first-principles calculations to understand the energetics of 2D phases of binary compounds which can be referred to as strongly non-stoichiometric transition-metal dichalcogenides. We found that other intermediate metallic non-stoichiometric phases, which are energetically more favourable than pure 2D metals [3], can also exist.

[1] Komsa, H.-P. et al.; Native Defects in Bulk and Monolayer MoS 2 from First Principles. Phys. Rev. B 2015, 91 (12), 125304.

[2] X. Zhao et al.; Atom-by-Atom Fabrication of Monolayer Molybdenum Membranes. Advanced Materials 2018, 30 (23), 1707281.

[3] T. Joseph et al.; Nonstoichiometric Phases of Two-Dimensional Transition-Metal Dichalcogenides: From Chalcogen Vacancies to Pure Metal Membranes. J. Phys. Chem. Lett. 2019, 10 (21), 6492.