Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 2: 2D Materials: Session I (joint session DS/CPP/HL)

DS 2.10: Vortrag

Montag, 12. März 2018, 12:00–12:15, H 2032

Structural changes and phase stability of Ti doped MoS₂ monolayers — •Andrea Silva, Tomas Polcar, Ondrej Hovorka, and Denis Kramer — Faculty of Engineering and Environment, University of Southampton, SO17 1BJ Southampton, United Kingdom

The discovery of graphene and its remarkable properties has renewed interest in inorganic materials and drawn attention to two-dimensional systems. Transition metal dichalcogenides (TMDs) have been known for decades in industry, but only recently their graphite-like layered structure has renewed academic interest. Quantum confinement in the monolayers yields different electronic properties compared to bulk counterparts. Moreover, TMDs are more chemically versatile than graphene, allowing easy functionalization of the layers [1]. Understanding the doping possibilities for TMDs is a key step in exploiting their potential.

In this study, we focus on the Ti doped MoS₂ TMD, a recently proposed new material with enhanced tribological properties [2].

In order to address the challenging task of determining the phase-stability of a new compound, we map energy landscapes obtained with DFT onto a cluster-expansion hamiltonian and iteratively search for low energy orderings of the atoms inside the given host. This methodology allows us to explore the Ti-Mo-S phase space and determine doping possibilities leading to stable phases of the form Ti_xMo_1−xS₂, quantify miscibility gaps and thermodynamic competition with ternary oxides.

[1] M. Chhowalla et al., Nat. Chem. 5, 263 (2013).

[2] A. Cammarata and T. Polcar, Inorg. Chem. 54, 5739 (2015).