The DFG has funded the CRC TRR288 ELASTO-Q-MAT initiative. It involves the JGU (Sinova co-speaker), Goethe University Frankfurt (Roser Valenti as coordinator and speaker), the Karlsruhe Institute of Technology (Joerg Schmalian co-speaker), and the Max Plank Institutes in Mainz and Dresden. This initiative has the goal to understand, advance, and exploit new physical phenomena emerging from a particularly strong coupling between a material's elasticity and its electronic quantum phases. To this end, we will study the effects of elastic tuning and elastic response of various types of electronic order in representative classes of quantum materials that share a high sensitivity to intrinsic strain or externally applied stress fields
A joint publication by the Organic Spintronics Team showing how key spintronic properties of organic molecules adsorbed at a solid surface may be precisely tuned by modifying the adsorbate structure has been published in Physical Review Letters.
More precisely, experiments performed by our collaborators at Cambridge University (UK), show a broadening of the electron spin resonance (ESR) linewidth upon spin injection from a permalloy surface into thin films of DNTT-based organic molecules. This broadening depends sensitively on the composition and surface bonding of the adsorbate molecules.
With the support of theoretical calculations performed by collaborators at Mons University (BE), significant differences in, e.g., the spin diffusion lengths of the organic adsorbate layers can be inferred from the measured variations in ESR linewidth.
A publication by the Organic Spintronics Team (OST) revising the established method for calculation of molecular spin admixture parameters from first-principles electronic structure theory has been published in Physical Review B. Spin states in a semi-conductor or molecule are a mixture of up and down, because of spin-orbit coupling (SOC). Spin admixture is one of the main ways in which SOC influences the spin dynamics in a molecular material.
The revised method for calculating spin admixture improves on a number of approximations made in the previous method, resulting in greater accuracy and transferability. Still, this method relies on efficient, standard electronic structure theory only, making it easy to implement, and suitable for large-scale calculations.
The group would like to congratulate Bertrand, who will start in October his new position at Chercheur Qualifié at the Fond National de Recherche Scientifique (FNRS) in Belgium. He will be associated with the University of Liège in the Quantum Materials (Q-mat) research unit, which is part of the Complex and Entangled Systems from Atoms to Materials department (CESAM). He will be establishing and building a group focusing on developing computational methods and researching magnetism and metals looking at skyrmion physics, transport and superconductivity.
A publication by the Organic Spintronics Team (OST) has been published in the Journal of Physical Chemistry C.
This paper presents an application of the recently developed technique for predictions of spin-admixture in molecules. As a computationally robust and efficient, "high-throughput" technique, it is used to describe general trends of in the spin admixture of several classes of molecules, from complex single-molecule magnets to organic polymers. The results emphasize the often counterintuitive variations of molecular spin-orbit coupling with molecular chemical composition and structure.
This paper presents an investigation of ultrafast dynamics in antiferromagnets which is a part of a developing field of an Antiferromagnetic spintronics.By performing magneto-optical pump-probe experiments we excite coherent longitudinal oscillations of the antiferromagnetic order parameter that cannot be described by a thermodynamic Landau-Lifshitz approach. We interpret these oscillations as manifestation of an entanglement of pairs of magnons generated by femtosecond optical pulses. The results open a way to creation and manipulation of quantum entanglement in antiferromagnetic systems at macroscopic scales.
A joint publication by the Organic Spintronics Team (OST) and collaborators from the ERC Synergy Project, the Max-Planck Institute for Polymer Research in Mainz and the University in Mons (Belgium) has been published in Nature Physics.
This paper presents a novel experimental perspective on spin and charge dynamics in high-mobility polymers, supported by calculations of the spin admixture distribution in realistic, large-scale polymer morphology models performed by the OST.
A joint publication by the Organic Spintronics Team and other ERC Synergy Project collaborators has been published in Nature Electronics. This paper presents experimental measurements of extremely long spin diffusion lengths in high-mobility organic polymer materials.
Modeling by the Organic Spintronics Team explains this finding in terms of the weak up-down spin mixing found in planar conjugated polymers with weak spin-orbit coupling.