Microscopic understanding of the current induced spin selectivity in chiral molecular systems

• Applicant: Professor Dr. Christoph Tegenkamp
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 508115456

The current induced spin selectivity process in chiral molecular systems gathered a lot of interest, as the propagation of electrons along the chiral backbone structure results in a pronounced spin polarization even at ambient conditions. Despite the robustness of this effect, the microscopic model is incomplete and the effect itself is not entirely understood. Here we propose a surface science approachusing scanning tunneling microscopy to study this effect on the atomic scale with single moleculeresolution. The adsorption of polypeptides from solution onto magnetic Au/Co/Au heterostructures allows us to measure quantitatively the spin polarization in helical molecules. Thereby, the flexibilityof α-helix polyalanine molecules is used here to study systematically the transport through molecules and surfaces with adsorbed molecules to determine the influence of the molecular lengths, sequencing, helicity, number of neighbors and coupling towards the current induced molecular spin selectivityand magnetism induced by proximity of adsorbed chiral molecules.

• DFG Programme: Research Grants