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Elsevier, Surface Science, 23-24(605), p. 2087-2091

DOI: 10.1016/j.susc.2011.08.011

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First-principles calculations of the thermal stability of Ti3SiC2(0001) surfaces

Journal article published in 2011 by Walter Orellana ORCID, Gonzalo Gutiérrez
This paper is available in a repository.
This paper is available in a repository.

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Abstract

The energetic, thermal stability and dynamical properties of the ternary layered ceramic Ti3SiC2(0001) surface are addressed by density-functional theory calculations and molecular dynamic (MD) simulations. The equilibrium surface energy at 0 K of all terminations is contrasted with thermal stability at high temperatures, which are investigated by ab initio MD simulations in the range of 800 to 1400 °C. We find that the toplayer (sublayer) surface configurations: Si(Ti2) and Ti2(Si) show the lowest surface energies with reconstruction features for Si(Ti2). However, at high temperatures they are unstable, forming disordered structures. On the contrary, Ti1(C) and Ti2(C) despite their higher surface energies, show a remarkable thermal stability at high temperatures preserving the crystalline structures up to 1400 °C. The less stable surfaces are those terminated in C atoms, C(Ti1) and C(Ti2), which at high temperatures show surface dissociation forming amorphous TiCx structures. Two possible atomic scale mechanisms involved in the thermal stability of Ti3SiC2(0001) are discussed.Highlights► Ab initio molecular dynamics claculations of Ti3 SiC2 (0001)-(3 ×3) surfaces. ► Si(Ti2) and Ti2(Si) are the most stable terminations at 0 K. ► At high temperatures, Ti1(C) and Ti2(C) show thermal stability up to 1400 C. ► Other terminations show instabilities, associated to Si-Si and C-C bonding.