Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 48: Focus Session: Spin Phenomena in Chiral Molecular Systems II (joint session O/TT)

O 48.4: Talk

Wednesday, March 20, 2024, 11:45–12:00, MA 141

Chirality-induced spin selective quantum capacitance — •Theiler Pius Markus — ETH Zürich, Zürich, Switzerland

The absence of symmetries has a significant impact on physics, particularly in chiral molecules or crystals lacking mirror symmetry. When an electric charge interacts with such chiral materials, the spin of the charge aligns even at room temperature. This spin polarization is known as chirality-induced spin selectivity (CISS). Although the exact mechanism behind the effect remains unclear, it may have played a role in the origin of life and significantly impacted biological processes. The effect has potential applications in chemical catalysis, renewable energy, and quantum technologies. This work aims to elucidate the key mechanism behind CISS surface potential changes upon toggling the enantiomer or magnetic polarization of the substrate. For the first time, chiral α-helical polypeptide films are investigated with time-resolved Kelvin-probe atomic force microscopy to probe the dynamics of the surface potential and a CISS quantum capacitance. This discovery of the CISS quantum capacitance leads to the conclusion that CISS is a persistent effect and paths the way to a fundamental reinterpretation of the CISS effect.

Keywords: chirality-induced spin selectivity; time-reversal symmetry; Kelvin-Probe force microscopy; quantum capacitance; toy model