Inhomogeneous relaxation of a molecular layer on an insulator due to compressive stress

Franck Bocquet (1) , Laurent Nony (1) , Stefan Mannsfeld (2) , Vincent Oison (1) , Rémy Pawlak (1) , Louis Porte (1) , Christian Loppacher (1)

1 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
2 SSRL SLAC - Stanford Synchrotron Radiation Lightsource

We discuss the inhomogeneous stress relaxation of a monolayer of hexahydroxytriphenylene (HHTP) which adopts the rare line-on-line (lol) coincidence on KCl(001) and forms Moiré patterns. The fact that the hexagonal HHTP layer is uniaxially compressed along the lol makes this system an ideal candidate to discuss the influence of inhomogeneous stress relaxation. Our work is a combination of noncontact atomic force microscopy experiments, of density functional theory and potential energy calculations, and of a thorough interpretation by means of the Frenkel-Kontorova model. We show that the assumption of a homogeneous molecular layer is not valid for this organic-inorganic heteroepitaxial system since the best calculated energy configuration correlates with the experimental data only if inhomogeneous relaxations of the layer are taken into account.

Mots clés: non-contact atomic force microscopy; organic molecules; ionic crystals; Density functional theory; inhomogeneous relaxation; Frenkel Kontorova model

Domaines: Agrégats Moléculaires et Atomiques [physics.atm-clus]

Franck Bocquet, Laurent Nony, Stefan Mannsfeld, Vincent Oison, Rémy Pawlak, et al.. Inhomogeneous relaxation of a molecular layer on an insulator due to compressive stress. 2012. ⟨hal-00702026⟩