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O: Fachverband Oberflächenphysik

O 69: Poster: Spin Phenomena in Chiral Molecular Systems

O 69.5: Poster

Mittwoch, 20. März 2024, 18:00–20:00, Poster C

Chiral-Induced Spin Selectivity and Non-equilibrium Spin Accumulation in Molecules and Interfaces: A First-Principles Study — •Sumit Naskar¹, Vladimiro Mujica², and Carmen Herrmann¹ — ¹Institute for Inorganic and Applied Chemistry HARBOR Bldg. 610 Luruper Chaussee 149, 22761 Hamburg, Germany — ²Arizona State University, School of Molecular Sciences, PO Box 871604, Tempe, Arizona 85287-1604, USA

Electrons moving through chiral molecules are selected according to their spin orientation and the helicity of the molecule, an effect known as chiral-induced spin selectivity (CISS)[1-2]. To help elucidate the underlying mechanism, a non-equilibrium Green's function method, combined with a Landauer approach and density functional theory, is applied to carbon helices contacted by gold electrodes, resulting in spin polarization in the non-equilibrium electronic structure of the junctions[3]. While this spin polarization is small calculated with a pure exchange-correlation functional, its sign changes with the direction of the current and with the handedness of the molecule[3]. Previous studies as well as our results suggest that computationally more expensive hybrid functionals may lead to considerably larger spin polarization in the electronic structure[4]. Thus non-equilibrium spin accumulation could be a key component in understanding the CISS mechanism.

References: [1] Goehler B. et. al., Science 2011, 6019, 894.; [2] Naaman R. et al., J. Phys. Chem. Lett. 2020, 11, 3660. [3] Naskar S. et al., J. Phys. Chem. Lett. 2023, 14, 694. [4] Zoellner M. et al., J. Chem. Theo. Comput. 2020, 16, 7357

Keywords: Non-equilibrium spin acuumulation; CISS effect; Spin-polarization; Coherent transport; DFT