https://doi.org/10.1140/epjb/e2014-50133-2
Regular Article
Electron transport in asymmetric biphenyl molecular junctions: effects of conformation and molecule-electrode distance*
Nanomaterials Research Group, Computational
Nanoscience & Technology Laboratory (CNTL), ABV-Indian Institute of
Information Technology and Management (ABV-IIITM), 474015
Gwalior,
India
a
e-mail: pankajs@iiitm.ac.in
Received:
27
February
2014
Received in final form:
13
June
2014
Published online:
24
September
2014
On the basis of ab-initio calculations, we predict the effect of conformation and molecule-electrode distance on transport properties of asymmetric molecular junctions for different electrode materials M (M = Au, Ag, Cu, and Pt). The asymmetry in these junctions is created by connecting one end of the biphenyl molecule to conjugated double thiol (model A) and single thiol (model B) groups, while the other end to Cu atom. A variety of phenomena viz. rectification, negative differential resistance (NDR), switching has been observed that can be controlled by tailoring the interface state properties through molecular conformation and molecule-electrode distance for various M. These properties are further analyzed by calculating transmission spectra, molecular orbitals, and orbital energy. It is found that Cu electrode shows significantly enhanced rectifying performance with change in torsion angles, as well as with increase in molecule-electrode distances than Au and Ag electrodes. Moreover, Pt electrode manifests distinctive multifunctional behavior combining switch, diode, and NDR. Thus, the Pt electrode is suggested to be a good potential candidate for a novel multifunctional electronic device. Our findings are compared with available experimental and theoretical results.
Key words: Mesoscopic and Nanoscale Systems
Supplementary material in the form of one pdf file available from the Journal web page at http//dx.doi.org/10.1140/epjb/e2014-50133-2
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2014