Probing Concepts in Single-Molecule Wires: Diodes, Electromechanics, FETs, Spinterfaces, etc.
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Probing Concepts in Single-Molecule Wires: Diodes, Electromechanics, FETs, Spinterfaces, etc.
CIC nanoGUNE Seminars
- Speaker
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Ismael Diez, University of Barcelona, Barcelona, Spain
- When
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2014/06/09
13:00
- Place
- nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
- Add to calendar
-
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**Host** : Luis Hueso
Single-molecule Junction approaches [1] have advanced the comprehension of
charge transport in a large variety of molecular backbones and brought fine
details on the molecule-electrode communication [2,3]. Latest efforts in this
field have been focused on the design of nanoscale molecular contacts with new
electrical functionalities [4,5].
The first block of this seminar will describe our latest implemented
methodologies to univocally identify the formation of single-molecule contacts
between two metal beads. The methods are based on the combination of DC-AC
current detection schemes when a small AC mechanical perturbation is
introduced along the main single-molecule junction axis [6].
For the second block, we have picked few examples that illustrate the
exploitation of previous methodologies to tailor single-molecule wires with
new electrical behaviors. The first case presents an example of controlling
diode (rectification) behavior in a single-molecule device [5]. Here we
demonstrate that it is possible to go from a perfectly symmetric to a highly
rectifying charge transport in a single-molecule junction by introducing
specific asymmetry within the molecular backbone. The second case shows an
example of a single-molecule device incorporating mechanical gating
capabilities [4]. The last example shows the design of single-molecule field
effect transistors (FET) by exploiting an electrochemical gate method [5].
Several examples of efficient current modulation on single-molecule contact
with this approach will be shown.
Last block of this seminar will focus on single-molecule wires built with more
complex organometallic backbones. Such molecular systems brought a number of
potential applications in nanoscale electrical interfaces, from highly
efficient molecular wires [7] to spin-dependent transport applications [8].
Two new examples will be brought here: first, spin-dependent transport in a
single-molecule contact built with an Fe(II)-based spin crossover (SCO)
compound is presented. Large magnetoresistance (>100%) is observed at low
applied biases depending upon the magnetization direction of a Ni electrode.
The second example illustrates the use of the metal coordination chemistry to
wire a single metalloporphyrin ring between two metal electrodes in a fully
flat conformation. This special geometry allows enhanced electrical coupling
between the metal electrodes and the molecule through the porphyrin metal
center.
**_References_**
[1]. Xu, B., Tao, NJ. _Science_ , **301** (2003) 1221.
[2]. Chen, F. _et al._ _JACS_ **128** (2006) 15874.
[3]. Díez-Pérez, I. _et al._ _Nature Nanotechnology_ __**6** __ (2011) 226.
[4]. Díez-Pérez, I. _et al._ _Nature Chemistry_ **1** (2009) 635.
[5]. Díez-Pérez, I. _et al._ _Nature Comm._ **1** (2010) 635.
[6]. J. Xia, I. Díez-Pérez, _et al._ _Nano Letters_ **8** (2008) 1960.
[7]. Gita Sedghi _et al._ ___Nature Nanotechnology_ **6** __ (2011) 517.
[8]. Burzurí, E. _et al._ _Physical Review Letters_ **109** , 147203 (2012).