An electron in a molecule is like a top spun in the right direction. Chiral molecules, twisted one way like a spiral staircase, let electrons pass only if they spin in a particular direction. This property is called chiral-induced spin selectivity, and it allows controlling spin without magnets.

Researchers built a multilayer structure from quantum dots, tiny crystals that glow when excited, and linked them with chiral molecules. They illuminated the sample with circularly polarized light (light whose electric field rotates in a circle) while applying a magnetic field. It turned out that the glow decay time depends on the magnitude and direction of the magnetic field, as well as on the direction of light rotation.

Such dependence indicates that the spin of an electron passing through a chiral molecule retains its polarization and precesses in the magnetic field like a top. The scientists built a model that accounts for spin precession and decay processes, and it reproduced the experimental data well.

This is the first time quantum coherence, the ability of spin to maintain its phase, has been observed in such systems at room temperature. Previously, such experiments required very low temperatures. Now chiral assemblies of quantum dots could become a platform for spintronics, electronics that uses electron spin, and quantum technologies.