Molecular scale energy dissipation in oligothiophene monolayers measured by dynamic force microscopy.
We perform a combined experimental and theoretical approach to establish the atomistic origin of energy dissipation occurring while imaging a molecular surface with an amplitude modulation atomic force microscope. We show that the energy transferred by a single nano-asperity to a sexithiophene monolayer is about 0.15 eV/cycle. The configuration space sampled by the tip depends on whether it approaches or withdraws from the surface. The asymmetry arises because of the presence of energy barriers among different deformations of the molecular geometry. This is the source of the material contrast provided by the phase-shift images.
Martínez
Nicolas F
NF
CSIC-Instituto de Microelectrónica de Madrid (IMM), Isaac Newton 8, Tres Cantos, Madrid, Spain.
Kamiński
Wojciech
W
Gómez
Carlos J
CJ
Albonetti
Cristiano
C
Biscarini
Fabio
F
Pérez
Rubén
R
García
Ricardo
R