FIRST-PRINCIPLES STUDIES ON THE PROPERTIES OF MOLECULAR WIRES

EZEQUIEL PEDRO M LEIVA

La Plata

Encuentro; HUMBOLDT KOLLEG-INTERNATIONAL CONFERENCE ON PHYSICS; 2011

Alexander von Humboldt Stiftung

Molecular electronics is an emerging field which has the ultimate objective of using individual molecules as constituting parts of electronic circuits. This developing technology, which represents the non plus ultra of circuit miniaturization, has the potential of replacing the actual semiconductor devices. Using molecules as building blocks is appealing, since it allows tailoring the properties of the contact either by modifying the nature of the anchoring group or by introducing different substituents on the molecule. However, dealing with such small objects has a number of handicaps that makes these systems the subject of extensive experimental and theoretical research. The present work is devoted to report on recent progress on the first-principles modelling of these tiny objects that were represented as molecular wires. By this term, we mean the thinnest contact that can be achieved between two conducting tips, made of a monatomic metallic wire with a molecule inserted in it. Some of the subjects that will be analyzed are: • Binding energy and rupture force of different molecular wires. • Long-term stability of pure and contaminated monatomic nanowires. • Effect of different molecular “alligator clips” for a given metal: S, N, COOH groups. • Inclusion of a benzene group with different substituents in the wire. • Use of different metals for the contact electrodes. • Studies of the system conductance for selected systems.