Now showing 1 - 2 of 2
  • Publication
    Unknown
    Multi-scale model predicting friction of crystalline materials
    (Wiley-VCH, 2021-12-13)
    Torche, Paola C.
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    Silva, Andrea
    ;
    ;
    Polcar, Tomas
    ;
    Hovorka, Ondrej
    A multi-scale computational framework suitable for designing solid lubricant interfaces fully in silico is presented. The approach is based on stochastic thermodynamics founded on the classical thermally activated 2D Prandtl–Tomlinson model, linked with first principles methods to accurately capture the properties of real materials. It allows investigating the energy dissipation due to friction in materials as it arises directly from their electronic structure, and naturally accessing the time-scale range of a typical friction force microscopy. This opens new possibilities for designing a broad class of material surfaces with atomically tailored properties. The multi-scale framework is applied to a class of 2D layered materials and reveals a delicate interplay between the topology of the energy landscape and dissipation that known static approaches based solely on the energy barriers fail to capture.
  • Publication
    Unknown
    Phase behaviour of (Ti:Mo) S2 binary alloys arising from electron-lattice coupling
    (Elsevier, 2020-09-25)
    Silva, Andrea
    ;
    Polcar, Tomas
    ;
    While 2D materials attract considerable interests for their exotic electronic and mechanical properties, their phase behaviour is still largely not understood. This work focuses on (Mo:Ti) S2 binary alloys which have captured the interest of the tribology community for their good performance in solid lubrication applications and whose chemistry and crystallography is still debated. Using electronic structures calculations and statistical mechanics we predict a phase-separating behaviour for the system and trace its origin to the energetics of the d-band manifold due to crystal field splitting. Our predicted solubility limits as a function of temperature are in accordance with experimental data and demonstrate the utility of this protocol in understanding and designing TMD alloys.