Probing Spin-Chirality Coupling in Molecular SAMs via Ballistic Quantum Transport in LaAlO3/SrTiO3

The chiral induced spin selectivity (CISS) effect demonstrates remarkable spin filtering by chiral molecules, yet the underlying mechanisms are not well understood [1]. We present a novel quantum transport platform using the LaAlO₃/SrTiO₃ (LAO/STO) interface to probe spin selectivity in chiral self-assembled monolayers (SAMs) under both equilibrium and non-equilibrium conditions. The LAO/STO system provides ballistic quantum wires with gate-tunable spin polarization, avoiding the need for ferromagnetic contacts [2]. In equilibrium, Onsager reciprocity requires the magnetoconductance to be symmetric with respect to the sign of magnetic field, which is confirmed experimentally. Under non-equilbrium conditions, Onsager reciprocity breaks down and we observe spin-dependent scattering that breaks the symmetry between B and -B.  This platform enables us to address fundamental questions about the nature of CISS and the interactions that lead to spin filtering in chiral materials.

[1] Bloom, B., et al., Chem. Rev. 124,1950−1991 (2024).

[2] Annadi, A., et al., Nano. Lett.18, 4473 (2018).