School of Natural and Environmental Sciences

Event items

Interpretation of STM results with the help of numerical calculations

NECEM Seminar - Dr Xavier Bouju, CEMES-CNRS, France

Date/Time: Wednesday 21 November 2018, 14:00 - 15:00

Venue: Lecture Theatre 1.46, Barbara Strang Teaching Centre, Bedson Building

Abstract

For decades, local-probe based methods like STM and AFM have demonstrated an extraordinary ability to provide images of molecules on various surfaces with atomic resolution as well as their capability to manipulate single atoms or molecules on surfaces with a high degree of precision.

In parallel to these experimental developments, an important theoretical effort of image interpretation has been performed.

Actually, due to many physical effects inherent in these techniques, calculations are necessary to explain experimental results, and theoretical models were proposed giving rise to several numerical codes, each of them having specific functionalities or at least having a particular range of validity.

More explicitly, an important step prior to the STM calculations themselves consists in performing molecular mechanics and/or dynamics simulations.

Indeed, the conformations of molecular adsorbates have to be determined inside the STM junction due to the interaction with the surface and with the probe tip in specific cases.

During this seminar, I shall show the set of examples obtained by our group in Toulouse.

A particular focus will be on the role of adatoms on the molecular self-assemble in the STM images.

Finally, numerical experiments have been conducted to explain the mechanical behaviour of adsorbed molecules and the controlled manipulations of molecular nanocars.

Biography

I am a CNRS research scientist working in CEMES-CNRS. My current research deals with calculations on chemical and physical properties of single molecules and molecular assemblies interacting with metallic, semiconducting, and insulating surfaces, with an emphasis on STM and AFM images calculations.