[Seminar] "Charge and spin transport in 2D materials – from graphene nanoribbons to magnetic heterostructures" by Prof.Mathias Kläui (Institute of Physics, Johannes Gutenberg-University)

Abstract: 2D materials have moved to the forefront of research recently due to exciting novel properties resulting from their dimensional confinement.
Graphene nanoribbons (GNRs) attract particular attention due to new physical properties resulting from their geometrical confinement. GNRs with atomically perfect edge structures can be synthesized on gold surfaces and transferred to insulating substrates [1,2]. 
We perform a systematic study on the conductivity and mobility of armchair GNRs. Temperature- dependent transport measurements reveal a universal scaling law valid for both aGNR5 and aGNR9 devices [3, 4]. Furthermore, we quantify the impact of the environmental on the device performance.
Temperature and gate sweep rate dependent measurements reveal charge carrier trapping as a main cause of the hysteresis. From the measurements, we are able to extract the density and energy of the trap states that generate the hysteresis [5] and the doping dependence [6].
Finally we investigate magnetic 2D materials, in particular focusing on antiferromagnets and spin transport [7,8].

[1] Narita et al., Nature Chem. 6, 126 (2014). 
[2] Chen et al., J. Am. Chem. Soc. 139 (28) (2017)
[3] Asadi et al., Nat. Commun. 4:1710 (2013) 
[4] Richter et al., Sci. Rep. 10, 1988 P(2020)
[5] Tries et al., Nano Lett. 20, 2993 (2020)
[6] Braatz et al., Phys. Rev. Mater. 5, 084003 (2021)
[7] Wu et al., Phys. Rev. Appl. 17, 064038 (2022)
[8] Balan et al., arxiv:2303.13167 (2023)

CV: Dr. Mathias Kläui is professor of physics at Johannes Gutenberg-University Mainz and adjunct professor at the Norwegian University of Science and Technology.
He received his PhD at the University of Cambridge, after which he joined the IBM Research Labs in Zürich. He was a junior group leader at the University of Konstanz and then became associate professor in a joint appointment between the EPFL and the PSI in Switzerland before moving to Mainz. His research focuses on nanomagnetism and spin dynamics on the nanoscale in new materials. His research covers from blue sky fundamental science to applied projects with major industrial partners. He has published more than 300 articles and given more than 200 invited talks. He is a Senior member of the IEEE and, a Fellow of the IOP and APS and has been awarded a number of prizes and scholarships.
He has been one of the 2020/2021 IEEE Magnetics Society Distinguished Lecturers.
Contact details and more information at www.klaeui-lab.de