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PGI Colloquium: Prof. Dr. Elke Scheer, University of Konstanz, Germany (Online Event)

Online Talk

Please note: You will receive the link to the online talk in the e-mail invitation, usually sent out a few days before the lecture takes place. It is also available on request from the contact person below.

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29 Oct 2021 11:00

Single-molecule functional devices

The possibility to fabricate electronic devices with functional building blocks of atomic size is a major driving force of nanotechnology. Key elements in microelectronics are reliable switches and memories as well as devices showing spin-dependent transport phenomena. Switches are usually realized by transistors and these components have been miniaturized all the way down close to the atomic scale. However, at such scales, three terminals, as required for transistors, are technically challenging to implement.

Single-molecule devices

Here I will present single-molecule transport experiments using the mechanically controlled break junction technique. The transport measurements were carried out at low temperatures down to 1.5K. I will first discuss the possibility to usephotochromic molecules as light-tunable conductance switches [1]. Recently, also the possibility to tune the conductance of single-molecules by magnetic fields has come to the focus.

The presence of an unpaired electron may give rise to intrinsic magnetic properties when coupled to nonmagnetic electrodes. I will discuss recent observations of magnetic-field tunable transport in two different classes of organic radical molecules [2]. We have observed very high positive and negative magnetoresistance up to 200% for a magnetic field of a few Tesla applied perpendicular to the current direction. We furthermore observe an interplay between Kondo peaks and magnetoresistance, the origin of which is still unknown and open for further investigation.

[1]. D. Sysoiev et al., Chem. Eur. J. 17, 6663 (2011), Y. Kim et al., Nano Letters 12, 3736 (2012), B.M. Briechle et al., Beilstein J. Nanotech. 3, 703 (2012), D. Sysoiev et al., Chem. Commun. 48, 11355 (2012), T. Sendler et al, Adv. Sci. 2, 201500017 (2015),  [2]. R. Hayakawa et al., Nano Letters 16, 4960 (2016), G. Mitra et al, in preparation.

Contact

Dr. Theodoulos Costi
Phone: +49 2461 61-4246
Fax: +49 2461 61-2620
email: t.costi@fz-juelich.de