Direct Observation of Large Quantum Interference Effect in Anthraquinone Solid-State Junctions
Author(s):
Vincent Rabache, Julien Chaste, Philippe Petit, Maria Luisa, Della Rocca, Pascal Martin, Jean-Christophe Lacroix, Richard L. McCreery, Philippe Lafarge
Journal:
Journal of the American Chemical Society
Year:
2013
Volume:
135
Pages
10218-10221
DOI:
10.1021/ja403577u
Abstract:
Quantum interference in cross-conjugated molecules embedded in solid-state devices was investigated by direct current–voltage and differential conductance transport measurements of anthraquinone (AQ)-based large area planar junctions. A thin film of AQ was grafted covalently on the junction base electrode by diazonium electroreduction, while the counter electrode was directly evaporated on top of the molecular layer. Our technique provides direct evidence of a large quantum interference effect in multiple CMOS compatible planar junctions. The quantum interference is manifested by a pronounced dip in the differential conductance close to zero voltage bias. The experimental signature is well developed at low temperature (4 K), showing a large amplitude dip with a minimum >2 orders of magnitude lower than the conductance at higher bias and is still clearly evident at room temperature. A temperature analysis of the conductance curves revealed that electron–phonon coupling is the principal decoherence mechanism causing large conductance oscillations at low temperature.