Dresden 2026 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 15: Phase Transformations I

MM 15.7: Vortrag

Dienstag, 10. März 2026, 15:30–15:45, SCH/A215

Critical-point wetting at crystal surfaces: Cahn-Hilliard residuum and occurence of first-order wetting transition — •Marine Bossert¹, Yong Li², and Jörg Weißmüller^1,2 — ¹Institute of Materials Physics and Technology, Hamburg University of Technology, Hamburg, Germany — ²Institute of Hydrogen Technology, Helmholtz Center Hereon, Geesthacht, Germany

Since its publication in 1958, the work by J.W. Cahn and J.E. Hilliard on the free energy of non-uniform systems [1] has been the basis for numerous studies, such as phase-field simulation of microstructure evolution or solute segregation to lattice defects. Cahn and Hilliard found that the second derivative (Laplacian) of the composition field governs the excess energy of systems with conserved networks of sites - such as crystals. A partial integration of the excess energy gives the gradient-square representation, which has been used in all follow-up works in an approximate form that neglects the partial integration residuum. Inspecting critical-point wetting at the surface of an Ising-type FCC crystal with a miscibility gap, this study shows that the solutions obtained with the (exact) second derivative or with the (approximate) gradient-square expressions for the free energy are in fact qualitatively different: the first-order wetting transition predicted by the gradient-square approach is not confirmed by the second-derivative one. Moreover, atomistic Monte-Carlo simulations confirm the absence of a first-order transition. [1] Cahn, J. W., & Hilliard, J. E. (1958).The Journal of Chemical Physics, 28(2), 258-267.

Keywords: Cahn-Hilliard; Crystal; Critical Point Wetting; Monte-Carlo simulation