Quantum tunnelling

Quantum mechanics

Quark

Magnetic field

Chemical physics

Intercalation (chemistry)

Materials science

Ferromagnetism

Superlattice

Nambu–Jona-Lasinio model

Chiral anomaly

Physics

Nanotechnology

Magnetoresistance

Fermion

Circular dichroism

Condensed matter physics

Crystallography

Chirality (physics)

Chemistry

Chiral symmetry breaking

Spintronics

Optoelectronics

Nature

The discovery of chiral-induced spin selectivity (CISS) opens up the possibility to manipulate spin orientation without external magnetic fields and enables new spintronic device designs1–4. Although many approaches have been explored for introducing CISS into solid-state materials and devices, the resulting systems so far are often plagued by high inhomogeneity, low spin selectivity or limited stability, and have difficulties in forming robust spintronic devices5–8. Here we report a new class of chiral molecular intercalation superlattices (CMIS) as a robust solid-state chiral material platform for exploring CISS. The CMIS were prepared by intercalating layered two-dimensional atomic crystals (2DACs) (such as TaS2 and TiS2) with selected chiral molecules (such as R-α-methylbenzylamine and S-α-methylbenzylamine). The X-ray diffraction and transmission electron microscopy studies demonstrate highly ordered superlattice structures with alternating crystalline atomic layers and self-assembled chiral molecular layers. Circular dichroism studies show clear chirality-dependent signals between right-handed (R-) and left-handed (S-) CMIS. Furthermore, by using the resulting CMIS as the spin-filtering layer, we create spin-selective tunnelling junctions with a distinct chirality-dependent tunnelling current, achieving a tunnelling magnetoresistance ratio of more than&nbsp;300&nbsp;per cent and a spin polarization ratio of more than&nbsp;60&nbsp;per cent. With a large family of 2DACs of widely tunable electronic properties and a vast selection of chiral molecules of designable structural motifs, the CMIS define a rich family of artificial chiral materials for investigating the CISS effect and capturing its potential for new spintronic devices. By intercalating layered 2D atomic crystals with selected chiral molecules, a new class of chiral molecular intercalation superlattices is reported, demonstrating highly ordered structures and achieving high tunnelling magnetoresistance and spin polarization ratios.

Chiral molecular intercalation superlattices