Chiral Mesostructured NiO Films with Spin Polarisation

Spin polarisation is found in the centrosymmetric nonferromagnetic crystals, chiral mesostructured NiO films (CMNFs), fabricated through the symmetry-breaking effect of a chiral molecule. Two levels of chirality were identified: primary nanoflakes with atomically twisted crystal lattices and secondary helical stacking of the nanoflakes. Spin polarisation of the CMNFs was confirmed by chirality-dependent magnetic-tip conducting atomic force microscopy (mc-AFM) and magnetic field-independent magnetic circular dichroism (MCD). Electron transfer in the symmetry-breaking electric field was speculated to create chirality-dependent effective magnetic fields. The asymmetric spin-orbit coupling (SOC) generated by effective magnetic fields selectively modifies the opposite spin motion in the antipodal CMNFs. Our findings provide fundamental insights for directional spin control in unprecedented functional inorganic materials.

Automated summary

Spin polarisation is achieved in chiral mesostructured NiO films (CMNFs) through symmetry breaking and the discovery of multi-level chirality. The study reveals that electron transfer in a chiral electric field generates effective magnetic fields and influences spin motion in the CMNFs.