Stretching and breaking of a molecular junction.
Density functional theory (DFT) calculations based on band structure are used to investigate the electromechanical properties of a molecular junction consisting of a dithiolbenzene molecule sandwiched between two gold slabs. This represents a prototypical system for the field of molecular electronics; such a system has previously been studied in break-junction measurements and electron-transport calculations. The stretching and breaking behavior of the junction is analyzed for different geometric conformations, and it is found that the breakage occurs through dissociation of one of the sulfur-gold bonds with a maximum force of 1.25 nN. The molecular electronic states shift during stretching, and, at the point of highest stress in the junction, the highest occupied molecular orbital (HOMO) of the molecule is located exactly at the Fermi level.
Romaner
Lorenz
L
School of Chemistry and Biochemistry and Center of Organic Photonics and Electronics, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, GA 30332-0400, USA.
Heimel
Georg
G
Gruber
Mathis
M
Brédas
Jean-Luc
JL
Zojer
Egbert
E
D001554:Benzene / Q000737:chemistry*; D004220:Disulfides; D006046:Gold / Q000737:chemistry*; D013816:Thermodynamics
D004220:Disulfides; D006046:Gold; D001554:Benzene