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SYMS: Symposium Spins in Molecular Systems: Strategies and Effects of Hyperpolarization

SYMS 1: Spins in Molecular Systems: Strategies and Effects of Hyperpolarization

SYMS 1.2: Invited Talk

Wednesday, March 19, 2025, 15:30–16:00, H1

The puzzle of spin and charge transport in the chirality induced spin selectivity effect — •Bart van Wees — Zernike Institute for Advanced Materials, University of Groningen, The Netherlands

I will present an overview of the current understanding of the chirality induced spin selectivity effect [1], as measured as a magnetoresistance in electronic devices and scanning probe geometries. I will describe the principles of chirality induced coupling of spin and charge currents, and show that this indeed allows to observe the specific chirality in non-linear transport experiments [2,3]. However, experiments at low bias, in the linear transport regime, show that Onsager's reciprocity relations are not obeyed. This, together with the large magnetoresistances which are observed, (sometimes exceeding 90% or more) are not compatible with descriptions in terms of spin (polarized) transport. I will discuss alternative mechanisms, which are based on the modification of the electrostatic potential profile, which depend on the interplay between chirality and magnetisation. These lead to a magnetoresistance due to a modification of the charge transport, not the spin transport. I will point out that open questions remain for these alternative mechanisms, and propose experimental stategies to address these. [1] Evers et al., Advanced Materials 34,13, 2106629 (2022) [2] X.Yang et al., Nano Letters 20, 8,6148 (2020) [3] X.Yang et al., Phys. Rev. B99, 024418 (2019 [4] S.H Tirion, and B.J. van Wees, ACS Nano 18/81, 6028 (2024) [5] Y. Zhao et al., ArXiv2201.03623v3

Keywords: spintronics; chirality induced spin selectivity; spin polarization; chiral molecules