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Layered material soaks up molecules to form an electron sieve
A simple method for incorporating molecules into the gaps of stacked semimetallic materials through immersion offers an efficient way of filtering electrons, which could be useful for information-storage technologies.
An extraordinary thing happens when electrons pass through a material made of chiral chemical species, which have a handedness that distinguishes them from their mirror image. The spin of each electron (its intrinsic angular momentum) determines whether it can pass through the material: electrons in ‘spin-up’ states might be favoured, whereas those in ‘spin-down’ states might be blocked, or vice versa. This effect is known as chiral-induced spin selectivity1,2 and it is useful for spintronics — the spin counterpart to electronics — in which information is stored in an electron’s spin as well as its charge. Chiral molecules provide particularly high spin selectivity, but they are difficult to integrate into solid-state spintronic devices. Writing in Nature, Qian and colleagues3 report a simple, effective technique for introducing chiral molecules between the layers of systems known as van der Waals materials, in which sheets comprising one or a few layers of covalently bonded atoms are stacked together.