Title :

Structural transitions in ordered supramolecular networks on a semiconductor surface

Author(s) :

Copie, Guillaume [Auteur]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Krzeminski, Christophe [Auteur]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Grandidier, B. [Auteur]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Cleri, Fabrizio [Auteur]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]

Conference title :

Materials Research Society Fall Meeting, MRS Fall 2013, Symposium WW : Self-Organization and Nanoscale Pattern Formation

City :

Boston, MA

Country :

Etats-Unis d'Amérique

Start date of the conference :

2013

English abstract : [en]

We report the experimental and theoretical study of the self-assembly of planar organic molecules of the type tris-X-biphenyl-benzene (with X=N, I, Br, CH) on a passivated, boron-doped Si(111)-√3x√3 (R=30°) surface. Ordered ...
Show more >We report the experimental and theoretical study of the self-assembly of planar organic molecules of the type tris-X-biphenyl-benzene (with X=N, I, Br, CH) on a passivated, boron-doped Si(111)-√3x√3 (R=30°) surface. Ordered molecular structures are observed by high-resolution STM. We perform multi-scale atomistic simulations, by DFT structure relaxation (Gaussian), metadynamics, molecular dynamics (MD) with empirical forces, and kinetic Monte Carlo with condensed degrees of freedom. Al low coverage, we identify by metadynamics the lowest-energy adsorption sites consistently with the STM images. Upon increasing molecular coverage, structural phase transitions of the molecular network are observed, in excellent agreement with experimental STM data. Our theoretical models allow to elucidate the subtle interplay between dispersion forces and hydrogen bonding, leading to some unexpected phenomena. Biasing the MD by a simple elastic-band constraint method, we identify the kinetic path leading from a low-density to a high-density ordered phase. Next, kinetic Monte Carlo simulations over a frozen Si:B surface, with energy parameters derived from the MD, help explaining the apparently striking experimental observations, according to which lower-density phases are favoured over higher-density phases.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Non spécifiée

Popular science :

Non

Collections :

• Institut d'Électronique, de Microélectronique et de Nanotechnologie (IEMN) - UMR 8520

Source :

Harvested from HAL