Molecular Materials: Electronic Properties
Molecular materials are exciting for physics because they combine the almost infinite design space of chemistry with the complexity of materials. Questions in our group include:
- How does current flow through a single molecule?- How can we measure and understand the thermoelectricity of single molecules?- How can we understand the interaction of the two-dimensional, atomically thin carbon material graphene with molecules?
At FAU, we work on molecular materials in a joint research approach of physics, chemistry and materials science. For this purpose, we are organized, among others, in the Interdisciplinary Institute for Molecular Materials (ICMM) and in the collaborative research center "Synthetic Carbon allotropes" (CRC 953).
Wir werden Experimente durchführen, in denen wir das Zusammenspiel von Graphen und organischen Molekülen mit elektrischen Methoden messen können. Wir beabsichtigen Einzelmolekülkontakte und flächige Graphen-Molekül-Graphen-Kontakte herzustellen, deren elektrische Transporteigenschaften wir detailliert untersuchen. Als Moleküle werden Polyyn-Drähte und andere molekulare Drähte verwendet. Weiterhin sind Moleküle mit Fulleren-Endgruppen von besonderem…
We perform single-molecule junction experiments. Our long-term goal is to understand and control charge transport across molecules. As a first step (first two years) within the priority program we will focus on methodological improvements. In this project we want to control charge states in single-molecule junctions. We will approach this goal by two means: First, we will redesign the experimental setup such that an electrostatic gate is available. Second, we will design and synthesize molecules,…
The interaction of molecules with metals has recently attracted increasing attention due to the appearance of molecular electronics as a candidate for future nanoelectronics. In this project, we will create and investigate systems where a molecule carries an unpaired spin. We propose to investigate two types of interaction between the spin degree of freedom and the conduction electrons in the metal: The first experiment is dedicated to the dynamical screening of the spin degree of freedom by the conduction electrons of the metal, a phenomenon which is closely related to the Kondo effect known in solid state metals with magnetic impurities. For that purpose, we will immobilize spin-bearing coordination compounds (e.g. FeII and CoII compounds) in single-molecule junctions. Thereby, the main observable parameter will be the I/V dependence of a current passing through the spin-bearing molecule. Second, we will investigate binuclear compounds with two spin degrees of freedom. Here, more complicated variations of Kondo physics can be explored. As a further reaching goal (and presumably beyond the two-year period for this grant), this research will guide towards Spintronics on the single-molecule level, where the electron transport can be controlled by the relative orientation of the two spins. The requirements to the molecules and the experiment are delicate and imperatively need a close cooperation between synthetic chemistry and experimental physics.
- Heiko B. Weber
- Popp MA., Erpenbeck A., Weber HB.:
Thermoelectricity of near-resonant tunnel junctions and their relation to Carnot efficiency
In: Scientific Reports 11 (2021), Article No.: 2031
- Wei T., Kohring M., Weber HB., Hauke F., Hirsch A.:
Molecular embroidering of graphene
In: Nature Communications 12 (2021), p. 552
- Popp MA., Weber HB.:
An ultra-stable setup for measuring electrical and thermoelectrical properties of nanojunctions
In: Applied Physics Letters 115 (2019), Article No.: 083108
- Ullmann K., Brana Coto P., Leitherer S., Molina-Ontoria A., Martin N., Thoss M., Weber HB.:
Single-Molecule Junctions with Epitaxial Graphene Nanoelectrodes
In: Nano Letters 15 (2015), p. 3512-3518
- Wagner S., Kißlinger F., Ballmann S., Schramm F., Chandrasekar R., Bodenstein T., Fuhr O., Secker D., Fink K., Ruben M., Weber HB.:
Switching of a coupled spin pair in a single-molecule junction
In: Nature Nanotechnology 8 (2013), p. 575-579