Regensburg 2016 – scientific programme
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DS: Fachverband Dünne Schichten
DS 41: Transport: Molecular Electronics and Photonics I
(Joint session of CPP, DS, HL, MA, O and TT, organized by TT)
DS 41.4: Talk
Thursday, March 10, 2016, 10:15–10:30, H23
Conductance trend in linear oligoacenes controlled by quantum size-effects — •Richard Korytar1, Tamar Yelin2, Nirit Sukenik2, Ran Vardimon2, Bharat Kumar3, Colin Nuckolls3, Oren Tal2, and Ferdinand Evers1 — 1Institute of Theoretical Physics, University of Regensburg, Germany — 2Chemical Physics Department, Weizmann Institute of Science, Rehovot, Israel — 3Department of Chemistry, Columbia University, New York, United States
In conventional electronics, the conductance of a wire decreases with length according to Ohm’s law. In molecular electronics, quantum effects lead to a richer phenomenology. Oligoacenes are organic molecules which consist of (linearly) fused benzene rings. Recently, Yelin et al. [submitted] studied conductance of oligoacenes directly coupled to Ag leads and found increase of conductance with molecular length.
I will show that transport through oligoacenes is governed by a quantum size effect which controls the alignment and width of the lowest unoccupied molecular orbital. These ideas will be supported by first-principles transport calculations using density-functional theory.
Linear oligoacenes are one of the simplest realizations of zig-zag
terminated graphene nano-ribbons. In the long-wire limit, I will demonstrate
that the conductance as a function of the molecular length shows surprising
oscillations with
period of approx. 11 rings [1].
R. Korytár, D. Xenioti, P. Schmitteckert,
M. Alouani, and F. Evers,
Nature Communications 5, 5000 (2014).