Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 57: Transport: Molecular Electronics I
TT 57.11: Talk
Wednesday, April 2, 2014, 12:30–12:45, HSZ 304
Large Fluctuation of Conductance in Oligo(phenylene ethynylene)-Based Molecular Junctions — •Daijiro Nozaki1, Cormac Toher2, and Gianaurelio Cuniberti1,3,4 — 1Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden, 01062 Dresden, Germany — 2Department of Mechanical Engineering and Materials Science, Duke University — 3Center for Advancing Electronics Dresden (cfAED), TU Dresden, 01062 Dresden, Germany — 4Dresden Center for Computational Materials Science (DCCMS), TU Dresden, 01062 Dresden, Germany
Oligo(phenylene ethynylene)s (OPEs) are widely used as conductive building blocks in molecular electronics. It is known that a phenylene unit in OPEs has low energy barrier (100 meV) for its rotation along the axis of the molecule. We have modeled an OPE-based molecular junction where an OPE oligomer is connected between conducting leads, and calculated the conductance of the junction using gDFTB code [1]. We show that the conductance at the Fermi energy significantly changes as a function of rotation angle of the phenylene unit yielding the on/off ratio over 104. We have also performed the ab initio MD at room temperature and obtained the similar result. This result implies that a special attention needs to be paid to the relationship between conductance and fluctuation of molecular framework.
D. Nozaki, C. Toher, and G. Cuniberti, J. Phys. Chem. Lett. 4, 4192 (2013)