Exploring chirality for spin control in quantum information

The interplay between structural chirality and magnetism is at the origin of many fascinating phenomena, and molecular materials are very promising candidates. For instance, giant magneto-chiral dichroism has been observed on a molecular helix^. As far as control is concerned, chiral materials can exhibit a linear spin-electric field with the possibility to control magnetic anisotropy and, more exotically, magnetic exchange² by means of an electric field. Electric fields have been also employed to promote electron transport through a chiral structure grafted on a metallic surface, thus providing evidence of a spin-filtering mechanism without the need for a magnetic field. Such phenomenon, known as chirality-induced spin selectivity, CISS,³ works also at high temperatures, a significant advantage for spin-based quantum information and other applications. To fully harness the potential of CISS we have started to investigate the CISS phenomenon at the intramolecular level by using magnetic resonance techniques to directly quantify the spin polarization. We have recently proposed experiments⁴ to be performed on a donor-acceptor dyad linked by a chiral bridge, where the electron transfer (ET) is promoted by light excitation of the donor or acceptor. The effect of spin-filtering in the ET can be detected by time-resolved EPR spectroscopy.⁵ In addition, microwave pulses can be used to transfer the chirality-induced spin polarization to a molecular spin qubit, thus enabling an innovative control mechanism.



1 Sessoli, R., et al. , A. Strong magneto-chiral dichroism in a paramagnetic molecular helix observed by hard X-rays. Nat. Phys. 11, 69-74 (2015).

2 Fittipaldi, M., et al. Electric field modulation of magnetic exchange in molecular helices. Nat. Mater. 18, 329-334 (2019).

3 Naaman, R., Paltiel, Y. & Waldeck, D. H. Chiral molecules and the electron spin. Nat. Rev. Chem. 3, 250-260 (2019).

4 Chiesa, A., et al. Assessing the Nature of Chiral-Induced Spin Selectivity by Magnetic Resonance. J. Phys. Chem. Lett. 12, 6341-6347 (2021).

5 Privitera, A., et al. . Direct detection of spin polarization in photoinduced charge transfer through a chiral bridge. Chem. Sci. 13, 12208 - 12218 (2022).