Chirality-Induced Spin Selectivity in Two-Dimensional Self-Assembled Molecular Networks

Chirality-induced spin selectivity (CISS) has been observed in a wide range of helical systems. Here, we report spin-selective electron transport through two-dimensional (2D) self-assembled molecular networks (SAMNs) formed by an enantiopure organic semiconductor with chiral alkyl side chains [dinaphtho[2,3-b:2',3'-f]thieno[3,2-<i>b</i>]thiophene (DNTT)] adsorbed on a magnetic substrate with perpendicular anisotropy. Scanning tunneling microscopy and scanning tunneling spectroscopy (STM and STS) were used to directly visualize the molecular arrangement on ferromagnetic surfaces and to measure the spin-dependent electron transport at the solution/solid interface, respectively. A comparison of enantiomorphous SAMNs under identical experimental conditions revealed an enantiospecific magnetic conductance asymmetry (EMA) exceeding 40% at room temperature. These asymmetries were observed when either the molecular enantiomer was changed or the magnetization direction was switched. Our results indicate that the CISS effect is also operative in nonhelical, one-atom-thick systems where the chirality is expressed in 2D, unlocking exciting opportunities for both fundamental research and practical applications.