Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 65: Transport: Molecular Electronics and Photonics 1
(Joint session of CPP, DS, HL, MA, O and TT organized by TT)

TT 65.4: Vortrag

Donnerstag, 10. März 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).