Physical Chemistry Seminar: The chirality induced spin-selectivity effect: a puzzle and it’s (possible) resolution

Abstract:

When electrons are injected through chiral molecules, the resulting current may become spin polarized. This effect, known as the chirality-induced spin-selectivity (CISS) effect, has been suggested to emerge due to the interplay between spin–orbit interactions and the chirality within the molecule. However, such explanations require unrealistically large values for the molecular spin–orbit interaction without any physical justification. Put simply, to date, the physical origin of  the CISS effect is unknown. 

I will present the “spinterface mechanism” for the CISS effect, based on the interplay between spin–orbit interactions in the electrode, the chirality of the molecule (which induces a solenoid field), and spin-transfer torque at the molecule–electrode interface. I will show the remarkable agreement between the spinterface theory and various experimental results, and will describe a set of “smoking gun” experiments for differentiating this mechanisms from other theoretical explanations. Finally, we will describe a spinterface mechanism for the CISS effect in photo-excited electrons scattered off a layer of chiral molecules. 

[1] S. Alwan & Y. Dubi, Spinterface Origin for the Chirality-Induced Spin-Selectivity Effect, J. Am. Chem. Soc. 143, 35, 14235–14241 (2021)

[2] Y. Dubi, Spinterface chirality-induced spin selectivity effect in bio-molecules, Chem. Sci., 13, 10878-1088 (2022).

[3] C. Yang, Y. Li, S. Zhou, Y. Guo, C. Jia, Z. Liu, K. N. Houk, Y. Dubi & X Guo, Real-time monitoring of reaction stereochemistry through single-molecule observations of chirality-induced spin selectivity, Nature Chemistry 15, 972–979 (2023)

[4] Seif Alwan, Subhajit Sarkar, Amos Sharoni, Yonatan Dubi, Temperature-dependence of the CISS effect from measurements in Chiral molecular intercalation super-lattices, J. Chem. Phys. 159, 014106 (2023).

[5] S. Alwan, A. Sharoni &  Y.  Dubi, Role of Electrode Polarization in the Electron Transport Chirality-Induced Spin-Selectivity Effect, J. Phys. Chem. C 128, 15, 6438–6445 (2024).
 

Seminar Organizer: Dr. Guy Cohen