A quantum circuit rule for interference effects in single-molecule electrical junctions.
A quantum circuit rule for combining quantum interference effects in the conductive properties of oligo(phenyleneethynylene) (OPE)-type molecules possessing three aromatic rings was investigated both experimentally and theoretically. Molecules were of the type X-Y-X, where X represents pyridyl anchors with para (p), meta (m) or ortho (o) connectivities and Y represents a phenyl ring with p and m connectivities. The conductances GXmX (GXpX) of molecules of the form X-m-X (X-p-X), with meta (para) connections in the central ring, were predominantly lower (higher), irrespective of the meta, para or ortho nature of the anchor groups X, demonstrating that conductance is dominated by the nature of quantum interference in the central ring Y. The single-molecule conductances were found to satisfy the quantum circuit rule Gppp/Gpmp=Gmpm/Gmmm. This demonstrates that the contribution to the conductance from the central ring is independent of the para versus meta nature of the anchor groups.
Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
David Zsolt
DZ
Manrique
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland.
Cancan
C
Huang
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland.
Masoud
M
Baghernejad
Department of Chemistry, Durham University, Durham DH1 3LE, UK.
Xiaotao
X
Zhao
1] Department of Physics, Lancaster University, Lancaster LA1 4YB, UK [2] Department of Laser Physics, Woman College of Science, University of Babylon, Iraq.
Oday A
OA
Al-Owaedi
Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
Hatef
H
Sadeghi
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland.
Veerabhadrarao
000000024361741X
V
Kaliginedi
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland.
Wenjing
W
Hong
Department of Chemistry, Durham University, Durham DH1 3LE, UK.
Murat
0000000303668201
M
Gulcur
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland.
Thomas
T
Wandlowski
Department of Chemistry, Durham University, Durham DH1 3LE, UK.
Martin R
MR
Bryce
Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
Colin J
CJ
Lambert